refactor(ui): rename route /korrespondenz → /briefwechsel

Update all internal links (AppNav, CoCorrespondentsList, goto) to the
new URL. No redirect needed — no production URLs exist yet.

Refs: #179

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/briefwechsel/+page.server.ts

@@ -0,0 +1,82 @@
+import { error } from '@sveltejs/kit';
+import type { components } from '$lib/generated/api';
+import { createApiClient } from '$lib/api.server';
+import { getErrorMessage } from '$lib/errors';
+
+export async function load({ url, fetch, locals }) {
+	const senderId = url.searchParams.get('senderId') || '';
+	const receiverId = url.searchParams.get('receiverId') || '';
+	const from = url.searchParams.get('from') || '';
+	const to = url.searchParams.get('to') || '';
+	const dir = url.searchParams.get('dir') || 'DESC';
+
+	const canWrite =
+		(locals.user as { groups?: { permissions: string[] }[] } | undefined)?.groups?.some((g) =>
+			g.permissions.includes('WRITE_ALL')
+		) ?? false;
+
+	const api = createApiClient(fetch);
+
+	let documents: components['schemas']['Document'][] = [];
+	let senderName = '';
+	let receiverName = '';
+
+	const requests: Promise<void>[] = [];
+
+	if (senderId) {
+		requests.push(
+			api
+				.GET('/api/documents/conversation', {
+					params: {
+						query: {
+							senderId,
+							receiverId: receiverId || undefined,
+							dir,
+							from: from || undefined,
+							to: to || undefined
+						}
+					}
+				})
+				.then((result) => {
+					if (!result.response.ok) {
+						const code = (result.error as unknown as { code?: string })?.code;
+						throw error(result.response.status, getErrorMessage(code));
+					}
+					documents = result.data ?? [];
+				})
+		);
+
+		requests.push(
+			api.GET('/api/persons/{id}', { params: { path: { id: senderId } } }).then((result) => {
+				if (!result.response.ok) {
+					const code = (result.error as unknown as { code?: string })?.code;
+					throw error(result.response.status, getErrorMessage(code));
+				}
+				const p = result.data as { firstName: string; lastName: string } | undefined;
+				if (p) senderName = `${p.firstName} ${p.lastName}`;
+			})
+		);
+	}
+
+	if (receiverId) {
+		requests.push(
+			api.GET('/api/persons/{id}', { params: { path: { id: receiverId } } }).then((result) => {
+				if (!result.response.ok) {
+					const code = (result.error as unknown as { code?: string })?.code;
+					throw error(result.response.status, getErrorMessage(code));
+				}
+				const p = result.data as { firstName: string; lastName: string } | undefined;
+				if (p) receiverName = `${p.firstName} ${p.lastName}`;
+			})
+		);
+	}
+
+	await Promise.all(requests);
+
+	return {
+		documents,
+		canWrite,
+		initialValues: { senderName, receiverName },
+		filters: { senderId, receiverId, from, to, dir }
+	};
+}

frontend/src/routes/briefwechsel/+page.svelte

@@ -0,0 +1,140 @@
+<script lang="ts">
+import { goto } from '$app/navigation';
+import { untrack } from 'svelte';
+import { SvelteURLSearchParams } from 'svelte/reactivity';
+import CorrespondenzPersonBar from './CorrespondenzPersonBar.svelte';
+import CorrespondenzFilterControls from './CorrespondenzFilterControls.svelte';
+import SinglePersonHintBar from './SinglePersonHintBar.svelte';
+import ConversationTimeline from './ConversationTimeline.svelte';
+import CorrespondenzEmptyState from './CorrespondenzEmptyState.svelte';
+import { m } from '$lib/paraglide/messages.js';
+
+let { data } = $props();
+
+// Filter values are local $state so swapPersons/toggleSort can mutate them before goto.
+// They are initialised once from server data and never re-synced — navigation replaces
+// the page component, so each load gets a fresh init.
+let senderId = $state(untrack(() => data.filters.senderId));
+let receiverId = $state(untrack(() => data.filters.receiverId));
+let fromDate = $state(untrack(() => data.filters.from));
+let toDate = $state(untrack(() => data.filters.to));
+let sortDir = $state(untrack(() => data.filters.dir));
+
+// Names are pure reads of server data — no local mutation needed.
+const senderName = $derived(data.initialValues.senderName);
+const receiverName = $derived(data.initialValues.receiverName);
+
+// Side-effect only: persist the resolved sender to localStorage once the name is available.
+$effect(() => {
+	if (data.filters.senderId && data.initialValues.senderName) {
+		persistRecentPerson(data.filters.senderId, data.initialValues.senderName);
+	}
+});
+
+const isSinglePerson = $derived(!!senderId && !receiverId);
+
+const RECENT_STORAGE_KEY = 'korrespondenz_recent_persons';
+const MAX_RECENT = 5;
+
+function persistRecentPerson(id: string, name: string) {
+	if (!id) return;
+	try {
+		const raw = localStorage.getItem(RECENT_STORAGE_KEY);
+		const existing: { id: string; name: string }[] = raw ? JSON.parse(raw) : [];
+		const filtered = existing.filter((p) => p.id !== id);
+		const updated = [{ id, name }, ...filtered].slice(0, MAX_RECENT);
+		localStorage.setItem(RECENT_STORAGE_KEY, JSON.stringify(updated));
+	} catch {
+		// localStorage unavailable — silently ignore
+	}
+}
+
+function applyFilters() {
+	const params = new SvelteURLSearchParams();
+	if (senderId) params.set('senderId', senderId);
+	if (receiverId) params.set('receiverId', receiverId);
+	if (fromDate) params.set('from', fromDate);
+	if (toDate) params.set('to', toDate);
+	params.set('dir', sortDir);
+	goto(`/briefwechsel?${params.toString()}`, { keepFocus: true });
+}
+
+function toggleSort() {
+	sortDir = sortDir === 'DESC' ? 'ASC' : 'DESC';
+	applyFilters();
+}
+
+function swapPersons() {
+	const tmp = senderId;
+	senderId = receiverId;
+	receiverId = tmp;
+	applyFilters();
+}
+
+function selectPerson(id: string) {
+	if (!id) {
+		document.querySelector<HTMLInputElement>('#senderId-search')?.focus();
+		return;
+	}
+	senderId = id;
+	receiverId = '';
+	applyFilters();
+}
+</script>
+
+<!-- Strips — pulled up to negate main's py-6 top padding so they sit flush -->
+<div class="-mt-6">
+	<!-- Strip: Row 1 — full width, no container -->
+	<CorrespondenzPersonBar
+		bind:senderId={senderId}
+		bind:receiverId={receiverId}
+		initialSenderName={data.initialValues.senderName}
+		initialReceiverName={data.initialValues.receiverName}
+		onapplyFilters={applyFilters}
+		onswapPersons={swapPersons}
+	/>
+
+	<!-- Strip: Row 2 — full width -->
+	<CorrespondenzFilterControls
+		senderId={senderId}
+		bind:fromDate={fromDate}
+		bind:toDate={toDate}
+		bind:sortDir={sortDir}
+		documentCount={data.documents.length}
+		onapplyFilters={applyFilters}
+		ontoggleSort={toggleSort}
+	/>
+
+	<!-- Single-person hint bar -->
+	{#if isSinglePerson}
+		<SinglePersonHintBar
+			senderName={senderName}
+			fromDate={fromDate || undefined}
+			toDate={toDate || undefined}
+			sortDir={sortDir}
+		/>
+	{/if}
+</div>
+
+<!-- Content area with padding -->
+<div class="px-[18px] py-[14px]">
+	{#if !senderId}
+		<CorrespondenzEmptyState onSelectPerson={selectPerson} />
+	{:else if data.documents.length === 0}
+		<div
+			class="flex flex-col items-center justify-center rounded-sm border border-line bg-muted py-24 text-center shadow-sm"
+		>
+			<p class="font-serif text-ink">{m.conv_no_results_heading()}</p>
+			<p class="mt-2 text-sm text-ink-3">{m.conv_no_results_text()}</p>
+		</div>
+	{:else}
+		<ConversationTimeline
+			documents={data.documents}
+			senderId={senderId}
+			receiverId={receiverId}
+			canWrite={data.canWrite}
+			senderName={senderName}
+			receiverName={receiverName}
+		/>
+	{/if}
+</div>

frontend/src/routes/briefwechsel/ConversationFilterBar.svelte

@@ -0,0 +1,142 @@
+<script lang="ts">
+import PersonTypeahead from '$lib/components/PersonTypeahead.svelte';
+import { m } from '$lib/paraglide/messages.js';
+
+let {
+	senderId = $bindable(''),
+	receiverId = $bindable(''),
+	fromDate = $bindable(''),
+	toDate = $bindable(''),
+	sortDir = $bindable('DESC'),
+	initialSenderName = '',
+	initialReceiverName = '',
+	onapplyFilters,
+	ontoggleSort,
+	onswapPersons
+}: {
+	senderId?: string;
+	receiverId?: string;
+	fromDate?: string;
+	toDate?: string;
+	sortDir?: string;
+	initialSenderName?: string;
+	initialReceiverName?: string;
+	onapplyFilters: () => void;
+	ontoggleSort: () => void;
+	onswapPersons: () => void;
+} = $props();
+</script>
+
+<div class="relative z-20 mb-10 border border-line bg-surface p-8 shadow-sm">
+	<div class="mb-6 grid grid-cols-1 items-end gap-4 md:grid-cols-[1fr_auto_1fr] md:gap-6">
+		<!-- Sender -->
+		<div
+			class="relative z-30 [&_input]:border-line [&_input]:py-2.5 [&_label]:mb-2 [&_label]:text-xs [&_label]:font-bold [&_label]:tracking-widest [&_label]:text-ink-2 [&_label]:uppercase"
+		>
+			<PersonTypeahead
+				name="senderId"
+				label={m.conv_label_person_a()}
+				bind:value={senderId}
+				initialName={initialSenderName}
+				restrictToCorrespondentsOf={receiverId || undefined}
+				onchange={() => onapplyFilters()}
+			/>
+		</div>
+
+		<!-- Swap button -->
+		<div class="{senderId && receiverId ? 'flex' : 'hidden md:flex'} items-end">
+			<button
+				data-testid="conv-swap-btn"
+				onclick={onswapPersons}
+				class="flex w-full items-center justify-center gap-2 border border-line px-3 py-2.5 text-xs font-bold tracking-widest text-ink uppercase transition-colors hover:bg-primary hover:text-primary-fg md:w-auto {senderId &&
+				receiverId
+					? ''
+					: 'invisible'}"
+				title={m.conv_swap_btn()}
+			>
+				<svg
+					class="h-4 w-4 flex-shrink-0 md:rotate-90"
+					fill="none"
+					stroke="currentColor"
+					viewBox="0 0 24 24"
+				>
+					<path
+						stroke-linecap="round"
+						stroke-linejoin="round"
+						stroke-width="2"
+						d="M7 16V4m0 0L3 8m4-4l4 4M17 8v12m0 0l4-4m-4 4l-4-4"
+					></path>
+				</svg>
+				<span class="md:hidden">{m.conv_swap_btn()}</span>
+			</button>
+		</div>
+
+		<!-- Receiver -->
+		<div
+			class="relative z-30 [&_input]:border-line [&_input]:py-2.5 [&_label]:mb-2 [&_label]:text-xs [&_label]:font-bold [&_label]:tracking-widest [&_label]:text-ink-2 [&_label]:uppercase"
+		>
+			<PersonTypeahead
+				name="receiverId"
+				label={m.conv_label_person_b()}
+				bind:value={receiverId}
+				initialName={initialReceiverName}
+				restrictToCorrespondentsOf={senderId || undefined}
+				onchange={() => onapplyFilters()}
+			/>
+		</div>
+	</div>
+
+	<div class="relative z-10 grid grid-cols-1 items-end gap-6 md:grid-cols-3">
+		<!-- Date From -->
+		<div>
+			<label
+				for="dateFrom"
+				class="mb-2 block text-xs font-bold tracking-widest text-ink-2 uppercase"
+				>{m.conv_label_from()}</label
+			>
+			<input
+				id="dateFrom"
+				type="date"
+				bind:value={fromDate}
+				onchange={() => onapplyFilters()}
+				class="block w-full border-line py-2.5 text-sm shadow-sm focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring"
+			/>
+		</div>
+
+		<!-- Date To -->
+		<div>
+			<label for="dateTo" class="mb-2 block text-xs font-bold tracking-widest text-ink-2 uppercase"
+				>{m.conv_label_to()}</label
+			>
+			<input
+				id="dateTo"
+				type="date"
+				bind:value={toDate}
+				onchange={() => onapplyFilters()}
+				class="block w-full border-line py-2.5 text-sm shadow-sm focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring"
+			/>
+		</div>
+
+		<!-- Sort Toggle -->
+		<div>
+			<button
+				onclick={ontoggleSort}
+				class="flex h-[42px] w-full items-center justify-center border border-line text-xs font-bold tracking-wide text-ink uppercase transition-colors hover:bg-primary hover:text-primary-fg"
+			>
+				<span class="mr-2">{m.conv_sort_label()}</span>
+				<span>{sortDir === 'DESC' ? m.conv_sort_newest() : m.conv_sort_oldest()}</span>
+				<svg
+					class="ml-2 h-4 w-4 transform {sortDir === 'ASC'
+						? 'rotate-180'
+						: ''} transition-transform"
+					fill="none"
+					stroke="currentColor"
+					viewBox="0 0 24 24"
+				>
+					<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 9l-7 7-7-7"
+					></path>
+				</svg>
+			</button>
+		</div>
+	</div>
+</div>

frontend/src/routes/briefwechsel/ConversationTimeline.svelte

@@ -0,0 +1,180 @@
+<script lang="ts">
+import { formatDate } from '$lib/utils/date';
+import { m } from '$lib/paraglide/messages.js';
+
+interface Props {
+	documents: {
+		id: string;
+		title?: string;
+		originalFilename: string;
+		documentDate?: string;
+		location?: string;
+		status: string;
+		sender?: { id: string; firstName: string; lastName: string } | null;
+		receivers?: { id: string; firstName: string; lastName: string }[];
+	}[];
+	senderId: string;
+	receiverId?: string;
+	canWrite: boolean;
+	senderName?: string;
+	receiverName?: string;
+}
+
+let { documents, senderId, receiverId, canWrite, senderName, receiverName }: Props = $props();
+
+const enrichedDocuments = $derived(
+	documents.map((doc, i) => {
+		const year = doc.documentDate ? new Date(doc.documentDate).getFullYear() : null;
+		const prevYear =
+			i > 0 && documents[i - 1].documentDate
+				? new Date(documents[i - 1].documentDate!).getFullYear()
+				: null;
+		const isOut = doc.sender?.id === senderId;
+		return { doc, year, showYearDivider: year !== null && year !== prevYear, isOut };
+	})
+);
+
+const countsByYear = $derived(
+	documents.reduce((acc, d) => {
+		if (d.documentDate) {
+			const y = new Date(d.documentDate).getFullYear();
+			acc.set(y, (acc.get(y) ?? 0) + 1);
+		}
+		return acc;
+	}, new Map<number, number>())
+);
+
+const outCount = $derived(documents.filter((d) => d.sender?.id === senderId).length);
+const inCount = $derived(documents.length - outCount);
+const outPct = $derived(documents.length > 0 ? (outCount / documents.length) * 100 : 0);
+
+const isBilateral = $derived(!!senderId && !!receiverId);
+
+const shortSenderName = $derived(senderName?.split(' ')[0] ?? senderName ?? '');
+const shortReceiverName = $derived(receiverName?.split(' ')[0] ?? receiverName ?? '');
+
+function statusDotClass(status: string): string {
+	const map: Record<string, string> = {
+		PLACEHOLDER: 'bg-brand-sand',
+		UPLOADED: 'bg-brand-mint',
+		TRANSCRIBED: 'bg-brand-mint',
+		REVIEWED: 'bg-brand-navy/70',
+		ARCHIVED: 'bg-brand-navy'
+	};
+	return map[status] ?? 'bg-brand-sand';
+}
+
+function otherPartyName(doc: (typeof documents)[number]): string {
+	if (doc.sender?.id === senderId) {
+		const r = doc.receivers?.[0];
+		return r ? `${r.firstName} ${r.lastName}` : m.conv_no_party();
+	}
+	return doc.sender ? `${doc.sender.firstName} ${doc.sender.lastName}` : m.conv_no_party();
+}
+
+const newDocUrl = $derived(
+	`/documents/new?senderId=${encodeURIComponent(senderId)}${receiverId ? `&receiverId=${encodeURIComponent(receiverId)}` : ''}`
+);
+</script>
+
+{#if isBilateral && documents.length > 0}
+	<div
+		class="flex flex-col gap-1 border-b border-line bg-muted px-[18px] py-2"
+		role="img"
+		aria-label="Briefverteilung in diesem Zeitraum: {outCount} von {senderName ?? ''}, {inCount} von {receiverName ?? ''}"
+	>
+		<div class="flex justify-between text-sm font-bold">
+			<span class="text-primary">{outCount} von {shortSenderName} →</span>
+			<span class="text-accent">{inCount} von {shortReceiverName} ←</span>
+		</div>
+		<div class="flex h-[5px] overflow-hidden rounded-full bg-line">
+			<div class="h-full bg-primary transition-all" style="width: {outPct}%"></div>
+			<div class="h-full bg-accent transition-all" style="width: {100 - outPct}%"></div>
+		</div>
+	</div>
+{/if}
+
+<div class="overflow-hidden rounded-sm border border-line bg-surface">
+	{#each enrichedDocuments as { doc, year, showYearDivider, isOut } (doc.id)}
+		{#if showYearDivider && year !== null}
+			<div
+				data-testid="year-divider"
+				class="flex items-baseline gap-3 border-t-2 border-b border-line bg-muted px-[14px] py-[8px]"
+			>
+				<span class="text-2xl font-black tracking-tight text-primary">{year}</span>
+				<span class="text-sm font-bold text-ink-3">{countsByYear.get(year) ?? 0} Briefe</span>
+			</div>
+		{/if}
+
+		<a
+			href="/documents/{doc.id}"
+			aria-label="{doc.title || doc.originalFilename}, {doc.documentDate
+				? formatDate(doc.documentDate)
+				: ''}"
+			class="group flex min-h-[44px] cursor-pointer items-center gap-[9px] border-b border-l-[3px] border-line-2 px-[14px] py-[10px] transition-colors last:border-b-0 hover:bg-muted"
+			class:border-l-primary={isOut}
+			class:border-l-accent={!isOut}
+		>
+			<span
+				class="w-[16px] shrink-0 text-sm font-black"
+				class:text-primary={isOut}
+				class:text-accent={!isOut}
+				aria-hidden="true"
+			>
+				{isOut ? '→' : '←'}
+			</span>
+
+			<div class="min-w-0 flex-1">
+				<div class="mb-[2px] truncate text-sm font-bold text-ink">
+					{doc.title || doc.originalFilename}
+				</div>
+				<div class="flex items-center gap-[5px] text-sm text-ink-3">
+					<span>{doc.documentDate ? formatDate(doc.documentDate) : '—'}</span>
+					{#if doc.location}
+						<span class="text-line">·</span>
+						<span>{doc.location}</span>
+					{/if}
+					{#if !receiverId}
+						<span class="text-line">·</span>
+						<span>{otherPartyName(doc)}</span>
+					{/if}
+					<span
+						class="ml-[3px] h-[6px] w-[6px] shrink-0 rounded-full {statusDotClass(doc.status)}"
+						title={doc.status}
+					></span>
+				</div>
+			</div>
+
+			<span
+				class="shrink-0 text-sm text-ink-3 opacity-0 transition-opacity group-hover:opacity-100"
+				aria-hidden="true">›</span
+			>
+		</a>
+	{/each}
+
+	{#if canWrite}
+		<div class="flex justify-end border-t border-line px-[14px] py-[6px]">
+			<a
+				href={newDocUrl}
+				data-testid="conv-new-doc-link"
+				class="inline-flex items-center gap-1 text-xs font-bold text-primary/50 transition-colors hover:text-primary"
+			>
+				<svg
+					class="h-3 w-3"
+					fill="none"
+					stroke="currentColor"
+					viewBox="0 0 24 24"
+					aria-hidden="true"
+				>
+					<path
+						stroke-linecap="round"
+						stroke-linejoin="round"
+						stroke-width="2"
+						d="M12 4v16m8-8H4"
+					/>
+				</svg>
+				{m.conv_new_doc_link()}
+			</a>
+		</div>
+	{/if}
+</div>

frontend/src/routes/briefwechsel/CorrespondentSuggestionsDropdown.svelte

@@ -0,0 +1,100 @@
+<script lang="ts">
+import { m } from '$lib/paraglide/messages.js';
+import { clickOutside } from '$lib/actions/clickOutside';
+
+interface Correspondent {
+	id: string;
+	firstName: string;
+	lastName: string;
+}
+
+interface Props {
+	correspondents: Correspondent[];
+	loading: boolean;
+	senderName: string;
+	onselect: (id: string) => void;
+	onclose: () => void;
+}
+
+let { correspondents, loading, senderName, onselect, onclose }: Props = $props();
+
+function getOptionElements(container: HTMLElement): HTMLElement[] {
+	return Array.from(container.querySelectorAll<HTMLElement>('[role="option"]'));
+}
+
+function handleKeydown(event: KeyboardEvent, container: HTMLElement) {
+	const options = getOptionElements(container);
+	const focused = document.activeElement as HTMLElement;
+	const idx = options.indexOf(focused);
+
+	if (event.key === 'ArrowDown') {
+		event.preventDefault();
+		const next = options[idx + 1] ?? options[0];
+		next?.focus();
+	} else if (event.key === 'ArrowUp') {
+		event.preventDefault();
+		const prev = options[idx - 1] ?? options[options.length - 1];
+		prev?.focus();
+	} else if (event.key === 'Escape') {
+		onclose();
+	}
+}
+
+function getInitials(person: Correspondent): string {
+	return `${person.firstName.charAt(0)}${person.lastName.charAt(0)}`.toUpperCase();
+}
+</script>
+
+<div
+	use:clickOutside
+	onclickoutside={onclose}
+	role="listbox"
+	tabindex="-1"
+	aria-label={m.conv_suggestions_heading()}
+	class="absolute top-full right-0 left-0 z-30 mt-1 rounded-sm border border-line bg-surface shadow-lg"
+	onkeydown={(e) => handleKeydown(e, e.currentTarget as HTMLElement)}
+>
+	<!-- Heading -->
+	<div class="px-3 pt-2 pb-1 text-[10px] font-bold tracking-widest text-ink-3 uppercase">
+		{m.conv_suggestions_heading()}
+	</div>
+
+	<!-- Correspondent rows -->
+	{#if !loading}
+		{#each correspondents as person (person.id)}
+			<div
+				role="option"
+				aria-selected="false"
+				tabindex="0"
+				class="flex cursor-pointer items-center gap-2 px-3 py-2 text-sm text-ink hover:bg-muted focus:bg-muted focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:ring-inset"
+				onclick={() => onselect(person.id)}
+				onkeydown={(e) => e.key === 'Enter' && onselect(person.id)}
+			>
+				<!-- Avatar with initials -->
+				<span
+					class="flex h-4 w-4 shrink-0 items-center justify-center rounded-full bg-primary text-[10px] font-bold text-primary-fg"
+					aria-hidden="true"
+				>
+					{getInitials(person)}
+				</span>
+				<!-- Svelte auto-escapes — do not use {@html} here. -->
+				{person.lastName}, {person.firstName}
+			</div>
+		{/each}
+	{/if}
+
+	<!-- Separator -->
+	<div class="mt-1 border-t border-line"></div>
+
+	<!-- "Alle Korrespondenten" row -->
+	<div
+		role="option"
+		aria-selected="false"
+		tabindex="0"
+		class="flex cursor-pointer items-center gap-2 px-3 py-2 text-sm text-ink hover:bg-muted focus:bg-muted focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:ring-inset"
+		onclick={() => onselect('')}
+		onkeydown={(e) => e.key === 'Enter' && onselect('')}
+	>
+		{m.conv_suggestions_all_label({ name: senderName })}
+	</div>
+</div>

frontend/src/routes/briefwechsel/CorrespondenzEmptyState.svelte

@@ -0,0 +1,120 @@
+<script lang="ts">
+import { onMount } from 'svelte';
+import { m } from '$lib/paraglide/messages.js';
+
+interface RecentPerson {
+	id: string;
+	name: string;
+}
+
+interface Props {
+	onSelectPerson: (id: string) => void;
+}
+
+const { onSelectPerson }: Props = $props();
+
+let recentPersons = $state<RecentPerson[]>([]);
+
+onMount(() => {
+	try {
+		const raw = localStorage.getItem('korrespondenz_recent_persons');
+		if (raw) {
+			// Svelte auto-escapes firstName/lastName — do not use {@html} with these values
+			recentPersons = JSON.parse(raw) as RecentPerson[];
+		}
+	} catch {
+		recentPersons = [];
+	}
+});
+</script>
+
+<div class="mx-auto flex max-w-lg flex-col items-center gap-5 py-12 text-center">
+	<!-- Icon circle -->
+	<div class="rounded-full bg-muted p-5">
+		<svg
+			xmlns="http://www.w3.org/2000/svg"
+			width="36"
+			height="36"
+			viewBox="0 0 24 24"
+			fill="none"
+			stroke="currentColor"
+			stroke-width="1.5"
+			stroke-linecap="round"
+			stroke-linejoin="round"
+			class="text-primary"
+			aria-hidden="true"
+		>
+			<rect x="2" y="4" width="20" height="16" rx="2" />
+			<path d="M2 7l10 7 10-7" />
+		</svg>
+	</div>
+
+	<!-- Heading -->
+	<h2 class="font-serif text-xl font-black text-ink">{m.conv_empty_heading()}</h2>
+
+	<!-- Subtext -->
+	<p class="max-w-sm text-base text-ink-3">
+		{m.conv_empty_text()}
+	</p>
+
+	<!-- Search input placeholder (visual only — clicking focuses Person A typeahead above) -->
+	<button
+		type="button"
+		data-testid="conv-empty-search"
+		aria-label={m.conv_empty_search_placeholder()}
+		onclick={() => onSelectPerson('')}
+		class="flex h-10 w-full max-w-sm items-center rounded border border-line bg-muted px-4 text-sm text-ink-3 italic transition-colors hover:border-primary"
+	>
+		<svg
+			xmlns="http://www.w3.org/2000/svg"
+			width="14"
+			height="14"
+			viewBox="0 0 24 24"
+			fill="none"
+			stroke="currentColor"
+			stroke-width="2"
+			stroke-linecap="round"
+			stroke-linejoin="round"
+			class="mr-2 shrink-0"
+			aria-hidden="true"
+		>
+			<circle cx="11" cy="11" r="8" />
+			<path d="m21 21-4.35-4.35" />
+		</svg>
+		{m.conv_empty_search_placeholder()}
+	</button>
+
+	<!-- Recent persons — only shown when localStorage has entries -->
+	{#if recentPersons.length > 0}
+		<!-- Divider -->
+		<div class="flex w-full max-w-sm items-center gap-2">
+			<div class="flex-1 border-t border-line"></div>
+			<span class="text-xs font-bold tracking-wider text-ink-3 uppercase">oder</span>
+			<div class="flex-1 border-t border-line"></div>
+		</div>
+
+		<div class="flex w-full max-w-sm flex-col items-center gap-3">
+			<span class="text-xs font-bold tracking-widest text-ink-3 uppercase">
+				{m.conv_empty_recent_label()}
+			</span>
+			<div class="flex flex-wrap justify-center gap-2">
+				{#each recentPersons as person (person.id)}
+					<!-- TODO: allow clearing recent history -->
+					<button
+						type="button"
+						onclick={() => onSelectPerson(person.id)}
+						class="flex items-center gap-2 rounded-full border border-line bg-surface px-4 py-2 text-sm font-bold text-ink transition-colors hover:border-primary hover:text-primary"
+					>
+						<span
+							class="flex h-5 w-5 shrink-0 items-center justify-center rounded-full bg-primary text-xs text-primary-fg"
+							aria-hidden="true"
+						>
+							{person.name.charAt(0).toUpperCase()}
+						</span>
+						{person.name}
+					</button>
+				{/each}
+			</div>
+		</div>
+	{/if}
+</div>

frontend/src/routes/briefwechsel/CorrespondenzFilterControls.svelte

@@ -0,0 +1,115 @@
+<script lang="ts">
+import { m } from '$lib/paraglide/messages.js';
+import DateInput from '$lib/components/DateInput.svelte';
+
+interface Props {
+	senderId: string;
+	fromDate?: string;
+	toDate?: string;
+	sortDir?: string;
+	documentCount?: number;
+	onapplyFilters: () => void;
+	ontoggleSort: () => void;
+}
+
+let {
+	senderId,
+	fromDate = $bindable(''),
+	toDate = $bindable(''),
+	sortDir = $bindable('DESC'),
+	documentCount,
+	onapplyFilters,
+	ontoggleSort
+}: Props = $props();
+
+let hasDateFilter = $derived(!!(fromDate || toDate));
+let isActive = $derived(!!(fromDate || toDate || sortDir !== 'DESC'));
+</script>
+
+<div
+	class="flex items-center gap-[10px] border-b border-line bg-muted px-4 py-[5px] transition-opacity sm:px-[18px]"
+	class:opacity-40={!senderId}
+	class:pointer-events-none={!senderId}
+	aria-disabled={!senderId}
+>
+	<!-- Period label -->
+	<span class="hidden text-xs font-bold tracking-wide text-ink-3 uppercase sm:block">
+		{m.conv_strip_period()}
+	</span>
+
+	<!-- From date -->
+	<DateInput
+		bind:value={fromDate}
+		onchange={() => onapplyFilters()}
+		placeholder={m.conv_strip_from_placeholder()}
+		class="h-8 w-[100px] rounded border bg-surface px-2 text-xs text-ink focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring {fromDate ? 'border-primary' : 'border-line'}"
+	/>
+
+	<span class="text-xs text-ink-3">–</span>
+
+	<!-- To date -->
+	<DateInput
+		bind:value={toDate}
+		onchange={() => onapplyFilters()}
+		placeholder={m.conv_strip_to_placeholder()}
+		class="h-8 w-[100px] rounded border bg-surface px-2 text-xs text-ink focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring {toDate ? 'border-primary' : 'border-line'}"
+	/>
+
+	<!-- Document count -->
+	<span
+		data-testid="conv-strip-count"
+		class="ml-auto text-xs font-bold"
+		class:text-primary={hasDateFilter}
+		class:text-ink-3={!hasDateFilter}
+	>
+		{m.conv_letters_count({ count: documentCount ?? 0 })}
+	</span>
+
+	<!-- Sort button -->
+	<button
+		data-testid="conv-sort-btn"
+		type="button"
+		aria-label="Sortierung umkehren"
+		aria-pressed={sortDir === 'ASC'}
+		onclick={ontoggleSort}
+		class="flex h-8 min-h-[44px] items-center gap-1 rounded border px-3 text-xs font-bold"
+		class:border-primary={isActive}
+		class:text-primary={isActive}
+		class:border-line={!isActive}
+		class:text-ink-3={!isActive}
+	>
+		{#if sortDir === 'ASC'}
+			{m.conv_strip_sort_oldest()}
+			<svg
+				xmlns="http://www.w3.org/2000/svg"
+				width="10"
+				height="10"
+				viewBox="0 0 24 24"
+				fill="none"
+				stroke="currentColor"
+				stroke-width="2.5"
+				stroke-linecap="round"
+				stroke-linejoin="round"
+				aria-hidden="true"
+			>
+				<polyline points="18 15 12 9 6 15" />
+			</svg>
+		{:else}
+			{m.conv_strip_sort_newest()}
+			<svg
+				xmlns="http://www.w3.org/2000/svg"
+				width="10"
+				height="10"
+				viewBox="0 0 24 24"
+				fill="none"
+				stroke="currentColor"
+				stroke-width="2.5"
+				stroke-linecap="round"
+				stroke-linejoin="round"
+				aria-hidden="true"
+			>
+				<polyline points="6 9 12 15 18 9" />
+			</svg>
+		{/if}
+	</button>
+</div>

frontend/src/routes/briefwechsel/CorrespondenzPersonBar.svelte

@@ -0,0 +1,129 @@
+<script lang="ts">
+import PersonTypeahead from '$lib/components/PersonTypeahead.svelte';
+import CorrespondentSuggestionsDropdown from './CorrespondentSuggestionsDropdown.svelte';
+
+interface Props {
+	senderId?: string;
+	receiverId?: string;
+	initialSenderName?: string;
+	initialReceiverName?: string;
+	onapplyFilters: () => void;
+	onswapPersons: () => void;
+}
+
+let {
+	senderId = $bindable(''),
+	receiverId = $bindable(''),
+	initialSenderName = '',
+	initialReceiverName = '',
+	onapplyFilters,
+	onswapPersons
+}: Props = $props();
+
+interface Correspondent {
+	id: string;
+	firstName: string;
+	lastName: string;
+}
+
+let swapVisible = $derived(!!(senderId && receiverId));
+
+let showSuggestions = $state(false);
+let correspondents = $state<Correspondent[]>([]);
+let loadingCorrespondents = $state(false);
+
+async function handleCorrespondentFocused() {
+	if (!senderId) return;
+	showSuggestions = true;
+	loadingCorrespondents = true;
+	try {
+		const res = await fetch(`/api/persons/${senderId}/correspondents`);
+		correspondents = res.ok ? await res.json() : [];
+	} catch {
+		correspondents = [];
+	} finally {
+		loadingCorrespondents = false;
+	}
+}
+
+function handleSuggestionSelect(id: string) {
+	receiverId = id;
+	showSuggestions = false;
+	onapplyFilters();
+}
+</script>
+
+<div class="flex items-end gap-[9px] border-b border-line bg-surface px-4 py-[9px] sm:px-[18px]">
+	<!-- Person A -->
+	<div class="min-w-0 flex-1">
+		<PersonTypeahead
+			name="senderId"
+			label="Person"
+			bind:value={senderId}
+			initialName={initialSenderName}
+			compact={true}
+			restrictToCorrespondentsOf={receiverId || undefined}
+			onchange={() => onapplyFilters()}
+		/>
+	</div>
+
+	<!-- Swap button -->
+	<button
+		data-testid="conv-swap-btn"
+		type="button"
+		aria-label="Personen tauschen"
+		onclick={onswapPersons}
+		class="flex h-9 w-9 shrink-0 items-center justify-center rounded border border-line bg-surface text-ink-3 transition-colors hover:border-primary hover:text-primary"
+		class:opacity-0={!swapVisible}
+		class:pointer-events-none={!swapVisible}
+		tabindex={swapVisible ? 0 : -1}
+	>
+		<svg
+			xmlns="http://www.w3.org/2000/svg"
+			width="14"
+			height="14"
+			viewBox="0 0 24 24"
+			fill="none"
+			stroke="currentColor"
+			stroke-width="2"
+			stroke-linecap="round"
+			stroke-linejoin="round"
+			aria-hidden="true"
+		>
+			<path d="M7 16V4m0 0L3 8m4-4l4 4" />
+			<path d="M17 8v12m0 0l4-4m-4 4l-4-4" />
+		</svg>
+	</button>
+
+	<!-- Korrespondent field -->
+	<div
+		class="relative min-w-0 flex-1"
+		class:[&_input]:border-dashed={!receiverId}
+		class:[&_input]:border-solid={!!receiverId}
+		class:[&_input]:bg-canvas={!receiverId}
+	>
+		<PersonTypeahead
+			name="receiverId"
+			label={receiverId ? 'Korrespondent' : 'Korrespondent — optional'}
+			bind:value={receiverId}
+			initialName={initialReceiverName}
+			compact={true}
+			placeholder="Alle Korrespondenten"
+			restrictToCorrespondentsOf={senderId || undefined}
+			onchange={() => {
+				showSuggestions = false;
+				onapplyFilters();
+			}}
+			onfocused={handleCorrespondentFocused}
+		/>
+		{#if showSuggestions && senderId && !receiverId}
+			<CorrespondentSuggestionsDropdown
+				correspondents={correspondents}
+				loading={loadingCorrespondents}
+				senderName=""
+				onselect={handleSuggestionSelect}
+				onclose={() => (showSuggestions = false)}
+			/>
+		{/if}
+	</div>
+</div>

frontend/src/routes/briefwechsel/SinglePersonHintBar.svelte

@@ -0,0 +1,50 @@
+<script lang="ts">
+import { m } from '$lib/paraglide/messages.js';
+
+interface Props {
+	senderName: string;
+	fromDate?: string;
+	toDate?: string;
+	sortDir?: string;
+}
+
+let { senderName, fromDate = '', toDate = '', sortDir = 'DESC' }: Props = $props();
+
+let hasDateFilter = $derived(!!(fromDate || toDate));
+let sortLabel = $derived(
+	sortDir === 'ASC' ? m.conv_strip_sort_oldest() : m.conv_strip_sort_newest()
+);
+let fromYear = $derived(fromDate ? fromDate.substring(0, 4) : '');
+let toYear = $derived(toDate ? toDate.substring(0, 4) : '');
+</script>
+
+<div
+	class="flex items-center gap-[5px] border-b border-accent bg-accent-bg px-[18px] py-[6px] text-xs text-ink"
+>
+	<svg
+		xmlns="http://www.w3.org/2000/svg"
+		width="14"
+		height="14"
+		viewBox="0 0 24 24"
+		fill="none"
+		stroke="currentColor"
+		stroke-width="1.5"
+		stroke-linecap="round"
+		stroke-linejoin="round"
+		aria-hidden="true"
+		class="shrink-0"
+	>
+		<path d="M9 5H7a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2V7a2 2 0 0 0-2-2h-2" />
+		<rect x="9" y="3" width="6" height="4" rx="1" />
+	</svg>
+
+	{#if hasDateFilter}
+		<strong>{senderName}</strong>
+		<span>·</span>
+		<span>{fromYear}–{toYear}</span>
+		<span>·</span>
+		<span>{sortLabel}</span>
+	{:else}
+		Alle Briefe von <strong>{senderName}</strong> — wähle einen Korrespondenten oben um einzugrenzen
+	{/if}
+</div>

frontend/src/routes/briefwechsel/page.server.spec.ts

@@ -0,0 +1,146 @@
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+import { load } from './+page.server';
+
+vi.mock('$lib/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/errors', () => ({ getErrorMessage: (code: string) => code ?? 'Unknown error' }));
+
+import { createApiClient } from '$lib/api.server';
+
+const writeUser = { groups: [{ permissions: ['WRITE_ALL'] }] };
+const readUser = { groups: [{ permissions: ['READ_ALL'] }] };
+
+function makeUrl(params: Record<string, string> = {}): URL {
+	const url = new URL('http://x/korrespondenz');
+	for (const [k, v] of Object.entries(params)) url.searchParams.set(k, v);
+	return url;
+}
+
+function mockApi(calls: { ok: boolean; data?: unknown; status?: number }[]) {
+	const GET = vi.fn();
+	for (const call of calls) {
+		GET.mockResolvedValueOnce({
+			response: { ok: call.ok, status: call.status ?? (call.ok ? 200 : 500) },
+			data: call.data,
+			error: call.ok ? undefined : { code: 'INTERNAL_ERROR' }
+		});
+	}
+	vi.mocked(createApiClient).mockReturnValue({ GET } as ReturnType<typeof createApiClient>);
+	return GET;
+}
+
+beforeEach(() => vi.clearAllMocks());
+
+// ─── No senderId ──────────────────────────────────────────────────────────────
+
+describe('korrespondenz load — no senderId', () => {
+	it('returns empty documents without calling the conversation endpoint', async () => {
+		const GET = mockApi([]);
+
+		const result = await load({
+			url: makeUrl(),
+			fetch: vi.fn() as unknown as typeof fetch,
+			locals: { user: readUser }
+		});
+
+		expect(result.documents).toEqual([]);
+		expect(GET).not.toHaveBeenCalled();
+	});
+});
+
+// ─── With senderId, no receiverId ────────────────────────────────────────────
+
+describe('korrespondenz load — senderId set, no receiverId', () => {
+	it('calls the conversation endpoint and the sender person endpoint', async () => {
+		const docs = [{ id: 'd1', title: 'Testbrief' }];
+		const GET = mockApi([
+			{ ok: true, data: docs },
+			{ ok: true, data: { firstName: 'Hans', lastName: 'Müller' } }
+		]);
+
+		const result = await load({
+			url: makeUrl({ senderId: 'p1' }),
+			fetch: vi.fn() as unknown as typeof fetch,
+			locals: { user: readUser }
+		});
+
+		expect(result.documents).toEqual(docs);
+		expect(result.initialValues.senderName).toBe('Hans Müller');
+		expect(result.initialValues.receiverName).toBe('');
+		expect(GET).toHaveBeenCalledTimes(2);
+	});
+});
+
+// ─── With senderId and receiverId ────────────────────────────────────────────
+
+describe('korrespondenz load — senderId and receiverId set', () => {
+	it('calls conversation, sender person, and receiver person endpoints', async () => {
+		const GET = mockApi([
+			{ ok: true, data: [] },
+			{ ok: true, data: { firstName: 'Hans', lastName: 'Müller' } },
+			{ ok: true, data: { firstName: 'Anna', lastName: 'Schmidt' } }
+		]);
+
+		const result = await load({
+			url: makeUrl({ senderId: 'p1', receiverId: 'p2' }),
+			fetch: vi.fn() as unknown as typeof fetch,
+			locals: { user: readUser }
+		});
+
+		expect(result.initialValues.senderName).toBe('Hans Müller');
+		expect(result.initialValues.receiverName).toBe('Anna Schmidt');
+		expect(GET).toHaveBeenCalledTimes(3);
+	});
+});
+
+// ─── canWrite derivation ─────────────────────────────────────────────────────
+
+describe('korrespondenz load — canWrite', () => {
+	it('derives canWrite true from WRITE_ALL permission', async () => {
+		mockApi([
+			{ ok: true, data: [] },
+			{ ok: true, data: { firstName: 'Hans', lastName: 'Müller' } }
+		]);
+
+		const result = await load({
+			url: makeUrl({ senderId: 'p1' }),
+			fetch: vi.fn() as unknown as typeof fetch,
+			locals: { user: writeUser }
+		});
+
+		expect(result.canWrite).toBe(true);
+	});
+
+	it('derives canWrite false when user lacks WRITE_ALL', async () => {
+		mockApi([
+			{ ok: true, data: [] },
+			{ ok: true, data: { firstName: 'Hans', lastName: 'Müller' } }
+		]);
+
+		const result = await load({
+			url: makeUrl({ senderId: 'p1' }),
+			fetch: vi.fn() as unknown as typeof fetch,
+			locals: { user: readUser }
+		});
+
+		expect(result.canWrite).toBe(false);
+	});
+});
+
+// ─── Backend error propagation ────────────────────────────────────────────────
+
+describe('korrespondenz load — backend error', () => {
+	it('throws when the conversation endpoint returns non-ok', async () => {
+		mockApi([
+			{ ok: false, status: 500 },
+			{ ok: true, data: { firstName: 'Hans', lastName: 'Müller' } }
+		]);
+
+		await expect(
+			load({
+				url: makeUrl({ senderId: 'p1' }),
+				fetch: vi.fn() as unknown as typeof fetch,
+				locals: { user: readUser }
+			})
+		).rejects.toMatchObject({ status: 500 });
+	});
+});

frontend/src/routes/briefwechsel/page.svelte.spec.ts

@@ -0,0 +1,246 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import Page from './+page.svelte';
+
+vi.mock('$app/navigation', () => ({ goto: vi.fn() }));
+
+afterEach(cleanup);
+
+// ─── Test data ────────────────────────────────────────────────────────────────
+
+const baseData = {
+	user: undefined,
+	canWrite: true,
+	canAnnotate: false,
+	documents: [],
+	initialValues: { senderName: '', receiverName: '' },
+	filters: { senderId: '', receiverId: '', from: '', to: '', dir: 'DESC' as const }
+};
+
+const withSender = {
+	...baseData,
+	initialValues: { senderName: 'Hans Müller', receiverName: '' },
+	filters: { ...baseData.filters, senderId: 'p1' }
+};
+
+const withPersons = {
+	...baseData,
+	initialValues: { senderName: 'Hans Müller', receiverName: 'Anna Schmidt' },
+	filters: { ...baseData.filters, senderId: 'p1', receiverId: 'p2' }
+};
+
+const makeDoc = (overrides: Record<string, unknown> = {}) => ({
+	id: 'd1',
+	title: 'Testbrief',
+	originalFilename: 'testbrief.pdf',
+	status: 'UPLOADED' as const,
+	documentDate: '1923-04-12',
+	location: 'Berlin',
+	metadataComplete: false,
+	sender: { id: 'p1', firstName: 'Hans', lastName: 'Müller' },
+	receivers: [{ id: 'p2', firstName: 'Anna', lastName: 'Schmidt' }],
+	tags: [],
+	transcription: undefined,
+	filePath: undefined,
+	createdAt: '1923-04-12T00:00:00Z',
+	updatedAt: '1923-04-12T00:00:00Z',
+	...overrides
+});
+
+const withDocs = {
+	...withPersons,
+	documents: [makeDoc()]
+};
+
+// ─── Empty state (no senderId) ────────────────────────────────────────────────
+
+describe('Korrespondenz page – empty state', () => {
+	it('shows the search heading when no person is selected', async () => {
+		render(Page, { data: baseData });
+		await expect.element(page.getByText(/Korrespondenz durchsuchen/i)).toBeInTheDocument();
+	});
+
+	it('shows the empty-search button', async () => {
+		render(Page, { data: baseData });
+		await expect.element(page.getByTestId('conv-empty-search')).toBeInTheDocument();
+	});
+
+	it('does not show the new document link when no person is selected', async () => {
+		render(Page, { data: baseData });
+		await expect.element(page.getByTestId('conv-new-doc-link')).not.toBeInTheDocument();
+	});
+
+	it('does not show a year divider when no person is selected', async () => {
+		render(Page, { data: baseData });
+		await expect.element(page.getByTestId('year-divider')).not.toBeInTheDocument();
+	});
+});
+
+// ─── Recent persons chips ─────────────────────────────────────────────────────
+
+describe('Korrespondenz page – recent persons', () => {
+	it('shows recent person chips from localStorage', async () => {
+		localStorage.setItem(
+			'korrespondenz_recent_persons',
+			JSON.stringify([{ id: 'r1', name: 'Clara Braun' }])
+		);
+		render(Page, { data: baseData });
+		await expect.element(page.getByText('Clara Braun')).toBeInTheDocument();
+		localStorage.removeItem('korrespondenz_recent_persons');
+	});
+
+	it('does not crash when localStorage contains corrupt JSON', async () => {
+		localStorage.setItem('korrespondenz_recent_persons', '}{not valid json');
+		render(Page, { data: baseData });
+		// Empty state heading is still shown — no chip list crash
+		await expect.element(page.getByText(/Korrespondenz durchsuchen/i)).toBeInTheDocument();
+		localStorage.removeItem('korrespondenz_recent_persons');
+	});
+});
+
+// ─── Single-person hint bar ───────────────────────────────────────────────────
+
+describe('Korrespondenz page – single-person hint bar', () => {
+	it('shows hint bar when only senderId is set', async () => {
+		render(Page, { data: withSender });
+		await expect.element(page.getByText(/Alle Briefe von Hans Müller/i)).toBeInTheDocument();
+	});
+
+	it('does not show hint bar when both persons are set', async () => {
+		render(Page, { data: { ...withPersons, documents: [makeDoc()] } });
+		await expect.element(page.getByText(/Alle Briefe von Hans Müller/i)).not.toBeInTheDocument();
+	});
+
+	it('does not show hint bar when no person is set', async () => {
+		render(Page, { data: baseData });
+		await expect.element(page.getByText(/Alle Briefe von/i)).not.toBeInTheDocument();
+	});
+});
+
+// ─── Filter controls disabled state ──────────────────────────────────────────
+
+describe('Korrespondenz page – filter strip Row 2 disabled state', () => {
+	it('renders filter controls with aria-disabled when no senderId', async () => {
+		render(Page, { data: baseData });
+		const strip = document.querySelector('[aria-disabled="true"]');
+		expect(strip).not.toBeNull();
+	});
+
+	it('filter controls are not aria-disabled when senderId is set', async () => {
+		render(Page, { data: withSender });
+		const strip = document.querySelector('[aria-disabled="false"]');
+		expect(strip).not.toBeNull();
+	});
+});
+
+// ─── Strip letter count ───────────────────────────────────────────────────────
+
+describe('Korrespondenz page – strip letter count', () => {
+	it('shows 0 Briefe when senderId is set but no documents', async () => {
+		render(Page, { data: withSender });
+		await expect.element(page.getByTestId('conv-strip-count')).toHaveTextContent('0 Briefe');
+	});
+
+	it('shows correct count when documents are loaded', async () => {
+		render(Page, { data: { ...withPersons, documents: [makeDoc()] } });
+		await expect.element(page.getByTestId('conv-strip-count')).toHaveTextContent('1 Briefe');
+	});
+});
+
+// ─── No results ───────────────────────────────────────────────────────────────
+
+describe('Korrespondenz page – no results', () => {
+	it('shows "no documents found" when a person is selected but there are no documents', async () => {
+		render(Page, { data: withSender });
+		await expect.element(page.getByText(/Keine Dokumente gefunden/i)).toBeInTheDocument();
+	});
+});
+
+// ─── Swap button ──────────────────────────────────────────────────────────────
+
+describe('Korrespondenz page – swap button', () => {
+	it('swap button is invisible when only one person is set', async () => {
+		render(Page, { data: withSender });
+		const btn = document.querySelector<HTMLElement>('[data-testid="conv-swap-btn"]');
+		expect(btn).not.toBeNull();
+		// opacity-0 is applied via class when swapVisible is false
+		expect(btn!.className).toMatch(/opacity-0/);
+	});
+
+	it('swap button is visible when both persons are set', async () => {
+		render(Page, { data: withPersons });
+		const btn = document.querySelector<HTMLElement>('[data-testid="conv-swap-btn"]');
+		expect(btn).not.toBeNull();
+		expect(btn!.className).not.toMatch(/opacity-0/);
+	});
+
+	it('calls goto with swapped sender and receiver when clicked', async () => {
+		const { goto } = await import('$app/navigation');
+		vi.mocked(goto).mockClear();
+		render(Page, { data: withPersons });
+		document.querySelector<HTMLElement>('[data-testid="conv-swap-btn"]')!.click();
+		expect(goto).toHaveBeenCalledWith(expect.stringContaining('senderId=p2'), expect.anything());
+		expect(goto).toHaveBeenCalledWith(expect.stringContaining('receiverId=p1'), expect.anything());
+	});
+});
+
+// ─── Year dividers ────────────────────────────────────────────────────────────
+
+describe('Korrespondenz page – year dividers', () => {
+	it('renders a year divider for the first document', async () => {
+		render(Page, { data: withDocs });
+		await expect.element(page.getByTestId('year-divider').first()).toHaveTextContent('1923');
+	});
+
+	it('renders a divider for each new year in the document list', async () => {
+		const data = {
+			...withPersons,
+			documents: [
+				makeDoc({ documentDate: '1923-04-12' }),
+				makeDoc({ id: 'd2', documentDate: '1965-08-03' })
+			]
+		};
+		render(Page, { data });
+		await expect.element(page.getByTestId('year-divider').first()).toHaveTextContent('1923');
+		await expect.element(page.getByTestId('year-divider').nth(1)).toHaveTextContent('1965');
+	});
+
+	it('does not render a second divider for documents from the same year', async () => {
+		const data = {
+			...withPersons,
+			documents: [
+				makeDoc({ documentDate: '1923-04-12' }),
+				makeDoc({ id: 'd2', documentDate: '1923-09-01' })
+			]
+		};
+		render(Page, { data });
+		await expect.element(page.getByTestId('year-divider').first()).toHaveTextContent('1923');
+		await expect.element(page.getByTestId('year-divider').nth(1)).not.toBeInTheDocument();
+	});
+});
+
+// ─── New document link ────────────────────────────────────────────────────────
+
+describe('Korrespondenz page – new document link', () => {
+	it('shows the link with correct href for a write user (bilateral)', async () => {
+		render(Page, { data: { ...withDocs, canWrite: true } });
+		const link = page.getByTestId('conv-new-doc-link');
+		await expect.element(link).toBeInTheDocument();
+		await expect.element(link).toHaveAttribute('href', expect.stringContaining('senderId=p1'));
+		await expect.element(link).toHaveAttribute('href', expect.stringContaining('receiverId=p2'));
+	});
+
+	it('shows the link with correct href for single-person mode', async () => {
+		render(Page, { data: { ...withSender, documents: [makeDoc()], canWrite: true } });
+		const link = page.getByTestId('conv-new-doc-link');
+		await expect.element(link).toBeInTheDocument();
+		await expect.element(link).toHaveAttribute('href', expect.stringContaining('senderId=p1'));
+		await expect.element(link).not.toHaveAttribute('href', expect.stringContaining('receiverId'));
+	});
+
+	it('hides the link for a read-only user', async () => {
+		render(Page, { data: { ...withDocs, canWrite: false } });
+		await expect.element(page.getByTestId('conv-new-doc-link')).not.toBeInTheDocument();
+	});
+});