feat(timeline): add EventTypeSelect segmented radio (PERSONAL/HISTORICAL)

grid-cols-2 segmented radio group modelled on PersonTypeSelector: role=radiogroup
with role=radio buttons, roving tabindex, radioGroupNav arrow-key support, and an
sr-only aria-live type-change announcement. Each option pairs a decorative
aria-hidden icon with a visible localized text label (icon is never the sole
differentiator), min-h-48px target. Emits a hidden input for form submission.

Refs #781
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/timeline/EventTypeSelect.svelte

@@ -0,0 +1,69 @@
+<script lang="ts">
+import { untrack } from 'svelte';
+import { radioGroupNav } from '$lib/shared/actions/radioGroupNav';
+import { m } from '$lib/paraglide/messages.js';
+
+type EventType = 'PERSONAL' | 'HISTORICAL';
+const TYPES: EventType[] = ['PERSONAL', 'HISTORICAL'];
+
+let {
+	value = 'PERSONAL',
+	name = 'type',
+	onchange
+}: { value?: string; name?: string; onchange?: (type: EventType) => void } = $props();
+
+let selected = $state<EventType>(
+	untrack(() => (TYPES.includes(value as EventType) ? (value as EventType) : 'PERSONAL'))
+);
+
+let announcement = $state('');
+
+const labels: Record<EventType, () => string> = {
+	PERSONAL: m.event_type_PERSONAL,
+	HISTORICAL: m.event_type_HISTORICAL
+};
+
+// Decorative accents only — never the sole differentiator (text label is always
+// present). aria-hidden so AT announces the label, not the glyph.
+const icons: Record<EventType, string> = {
+	PERSONAL: '👤',
+	HISTORICAL: '🏛'
+};
+
+function select(type: EventType) {
+	selected = type;
+	announcement = m.a11y_type_changed({ type: labels[type]() });
+	onchange?.(type);
+}
+</script>
+
+<div
+	role="radiogroup"
+	aria-label={m.event_editor_type_label()}
+	class="grid grid-cols-2 gap-2"
+	use:radioGroupNav={(v) => {
+		if (TYPES.includes(v as EventType)) select(v as EventType);
+	}}
+>
+	{#each TYPES as type (type)}
+		<button
+			type="button"
+			role="radio"
+			value={type}
+			aria-checked={selected === type}
+			tabindex={selected === type ? 0 : -1}
+			onclick={() => select(type)}
+			class="flex min-h-[48px] cursor-pointer items-center gap-2 rounded-sm border px-3 py-2 text-sm font-medium transition-colors focus-visible:ring-2 focus-visible:ring-focus-ring focus-visible:outline-none {selected ===
+			type
+				? 'border-primary bg-primary text-primary-fg'
+				: 'border-line bg-surface text-ink hover:border-primary/50'}"
+		>
+			<span class="text-lg leading-none" aria-hidden="true">{icons[type]}</span>
+			<span>{labels[type]()}</span>
+		</button>
+	{/each}
+</div>
+
+<input type="hidden" name={name} value={selected} />
+
+<div class="sr-only" aria-live="polite" aria-atomic="true">{announcement}</div>

frontend/src/lib/timeline/EventTypeSelect.svelte.spec.ts

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+import { afterEach, describe, expect, it } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import EventTypeSelect from './EventTypeSelect.svelte';
+
+afterEach(() => cleanup());
+
+describe('EventTypeSelect — segmented PERSONAL/HISTORICAL radio', () => {
+	it('renders exactly two radio options', async () => {
+		render(EventTypeSelect, { value: 'PERSONAL' });
+		const radios = document.querySelectorAll('[role="radio"]');
+		expect(radios.length).toBe(2);
+	});
+
+	it('marks the initial value as checked and seeds the hidden input', async () => {
+		render(EventTypeSelect, { value: 'HISTORICAL', name: 'type' });
+		const hidden = document.querySelector('input[type="hidden"][name="type"]') as HTMLInputElement;
+		expect(hidden.value).toBe('HISTORICAL');
+	});
+
+	it('selects HISTORICAL and updates the hidden input when clicked', async () => {
+		render(EventTypeSelect, { value: 'PERSONAL', name: 'type' });
+		await page.getByRole('radio', { name: 'Historisch' }).click();
+		const hidden = document.querySelector('input[type="hidden"][name="type"]') as HTMLInputElement;
+		expect(hidden.value).toBe('HISTORICAL');
+	});
+});