feat(stammbaum): person detail Beziehungen card

- persons/[id]/+page.server.ts loads relationships and
  inferred-relationships in the existing parallel fetch.
- New PersonRelationshipsCard renders direct chips (mint) and the
  top-5 derived chips (grey) on /persons/{id}, both linked to the
  other person's page. Empty state shows
  "Noch keine Beziehungen bekannt." in muted serif.
- Card sits in the right column above the document lists.

Refs #358.

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

frontend/src/routes/persons/[id]/+page.server.ts

@@ -11,11 +11,20 @@ export async function load({ params, fetch, locals }) {
 			g.permissions.includes('WRITE_ALL')
 		) ?? false;
 
-	const [personResult, sentDocsResult, receivedDocsResult, aliasesResult] = await Promise.all([
+	const [
+		personResult,
+		sentDocsResult,
+		receivedDocsResult,
+		aliasesResult,
+		relsResult,
+		inferredResult
+	] = await Promise.all([
 		api.GET('/api/persons/{id}', { params: { path: { id } } }),
 		api.GET('/api/persons/{id}/documents', { params: { path: { id } } }),
 		api.GET('/api/persons/{id}/received-documents', { params: { path: { id } } }),
-		api.GET('/api/persons/{id}/aliases', { params: { path: { id } } })
+		api.GET('/api/persons/{id}/aliases', { params: { path: { id } } }),
+		api.GET('/api/persons/{id}/relationships', { params: { path: { id } } }),
+		api.GET('/api/persons/{id}/inferred-relationships', { params: { path: { id } } })
 	]);
 
 	if (!personResult.response.ok) {
@@ -28,6 +37,8 @@ export async function load({ params, fetch, locals }) {
 		sentDocuments: sentDocsResult.data ?? [],
 		receivedDocuments: receivedDocsResult.data ?? [],
 		aliases: aliasesResult.data ?? [],
+		relationships: relsResult.data ?? [],
+		inferredRelationships: inferredResult.data ?? [],
 		canWrite
 	};
 }