feat(persons): add type selector + title + conditional fields to edit form

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

frontend/src/lib/components/PersonTypeSelector.svelte

@@ -6,7 +6,11 @@ import { m } from '$lib/paraglide/messages.js';
 const TYPES = ['PERSON', 'INSTITUTION', 'GROUP', 'UNKNOWN'] as const;
 type PersonType = (typeof TYPES)[number];
 
-let { value = 'PERSON', name = 'personType' }: { value?: string; name?: string } = $props();
+let {
+	value = 'PERSON',
+	name = 'personType',
+	onchange
+}: { value?: string; name?: string; onchange?: (type: PersonType) => void } = $props();
 
 let selected = $state<PersonType>(
 	untrack(() => (TYPES.includes(value as PersonType) ? (value as PersonType) : 'PERSON'))
@@ -21,6 +25,7 @@ const labels: Record<PersonType, () => string> = {
 
 function select(type: PersonType) {
 	selected = type;
+	onchange?.(type);
 }
 </script>