feat(person): date + precision controls on person new/edit forms

New PersonLifeDateField (German date input + hidden ISO + DAY/MONTH/YEAR
precision select, min-h-44px, sm: side-by-side) used for birth and death
in both forms. Legacy APPROX precision seeds the select as YEAR so an
untouched save never claims DAY. Server actions send date+precision
pairs or omit both; obsolete year i18n keys removed, 9 form keys added.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/lib/person/PersonLifeDateField.svelte

@@ -0,0 +1,96 @@
+<script lang="ts">
+import { onMount } from 'svelte';
+import { m } from '$lib/paraglide/messages.js';
+import { isoToGerman, handleGermanDateInput } from '$lib/shared/utils/date';
+import type { DatePrecision } from '$lib/shared/utils/documentDate';
+
+// Only DAY / MONTH / YEAR are offered for life dates: RANGE and SEASON make no
+// sense for a birth or death, and APPROX stays display-only for legacy imports (#773).
+const PERSON_DATE_PRECISIONS: { value: DatePrecision; label: () => string }[] = [
+	{ value: 'DAY', label: m.person_precision_day },
+	{ value: 'MONTH', label: m.person_precision_month },
+	{ value: 'YEAR', label: m.person_precision_year }
+];
+
+let {
+	name,
+	legend,
+	precisionLabel,
+	initialIso = '',
+	initialPrecision = null
+}: {
+	name: string;
+	legend: string;
+	precisionLabel: string;
+	initialIso?: string | null;
+	initialPrecision?: string | null;
+} = $props();
+
+let display = $state('');
+let iso = $state('');
+let precision = $state<DatePrecision>('DAY');
+
+// Seed once at mount (WhoWhenSection pattern): a later load() rerun must not
+// stomp the user's in-progress edit.
+onMount(() => {
+	if (initialIso) {
+		iso = initialIso;
+		display = isoToGerman(initialIso);
+	}
+	const offered = PERSON_DATE_PRECISIONS.some((p) => p.value === initialPrecision);
+	if (offered) {
+		precision = initialPrecision as DatePrecision;
+	} else if (initialIso) {
+		// Legacy APPROX/SEASON/RANGE precision is not editable here — seed YEAR so an
+		// untouched save does not silently claim DAY precision for the stored date.
+		precision = 'YEAR';
+	}
+});
+
+function handleInput(e: Event) {
+	const result = handleGermanDateInput(e);
+	display = result.display;
+	iso = result.iso;
+}
+
+const controlCls =
+	'block min-h-[44px] w-full rounded border border-line px-3 py-2 font-serif text-ink focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring';
+</script>
+
+<fieldset>
+	<legend class="mb-1 block text-xs font-bold tracking-widest text-ink-3 uppercase">
+		{legend}
+	</legend>
+	<div class="flex flex-col gap-2 sm:flex-row">
+		<div class="flex-1">
+			<input
+				id={name}
+				type="text"
+				inputmode="numeric"
+				placeholder="TT.MM.JJJJ"
+				maxlength="10"
+				aria-label={legend}
+				value={display}
+				oninput={handleInput}
+				class={controlCls}
+			/>
+			<input type="hidden" name={name} value={iso} />
+		</div>
+		<div class="flex-1">
+			<select
+				id="{name}Precision"
+				name="{name}Precision"
+				aria-label="{legend}: {precisionLabel}"
+				bind:value={precision}
+				class="{controlCls} bg-surface"
+			>
+				{#each PERSON_DATE_PRECISIONS as p (p.value)}
+					<option value={p.value}>{p.label()}</option>
+				{/each}
+			</select>
+		</div>
+	</div>
+	<p class="mt-1 font-sans text-xs text-ink-3">
+		{m.person_precision_hint()} · {m.person_date_placeholder_hint()}
+	</p>
+</fieldset>

frontend/src/lib/person/person-validation.ts

@@ -9,8 +9,10 @@ export type PersonFormData = {
 	firstName?: string | null;
 	lastName: string;
 	alias?: string | null;
-	birthYear?: number | null;
-	deathYear?: number | null;
+	birthDate?: string | null;
+	birthDatePrecision?: string | null;
+	deathDate?: string | null;
+	deathDatePrecision?: string | null;
 	generation?: number | null;
 	notes?: string | null;
 };