feat(frontend): update generated API types and Geschichte routes for JourneyItem model

- api.ts: add GeschichteType, JourneyItem, GeschichteSummary schemas;
  remove documentId param from list endpoint; change list response to
  GeschichteSummary[]; add type + items to Geschichte; remove documents field
- GeschichteEditor: remove DocumentMultiSelect + documentIds from payload
  (journey items are managed via the future Lesereisen editor, not here)
- GET /geschichten page: remove documentId filter from server load + URL logic
- geschichten/new: remove documentId pre-population from server load
- geschichten/[id]: replace g.documents with g.items (document-backed JourneyItems)
- geschichten/new + [id]/edit: remove documentIds from submit payload type

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

frontend/src/routes/geschichten/new/+page.server.ts

@@ -10,24 +10,14 @@ export const load: PageServerLoad = async ({ url, fetch, parent }) => {
 
 	const api = createApiClient(fetch);
 	const personId = url.searchParams.get('personId');
-	const documentId = url.searchParams.get('documentId');
 
-	const [personResult, documentResult] = await Promise.all([
-		personId
-			? api.GET('/api/persons/{id}', { params: { path: { id: personId } } })
-			: Promise.resolve(null),
-		documentId
-			? api.GET('/api/documents/{id}', { params: { path: { id: documentId } } })
-			: Promise.resolve(null)
-	]);
+	const personResult = personId
+		? await api.GET('/api/persons/{id}', { params: { path: { id: personId } } })
+		: null;
 
 	// Silently ignore 404/403 to avoid leaking entity existence on unknown IDs.
 	const initialPersons =
 		personResult && personResult.response.ok && personResult.data ? [personResult.data] : [];
-	const initialDocuments =
-		documentResult && documentResult.response.ok && documentResult.data
-			? [documentResult.data]
-			: [];
 
-	return { initialPersons, initialDocuments };
+	return { initialPersons };
 };

frontend/src/routes/geschichten/new/+page.svelte

@@ -17,7 +17,6 @@ async function handleSubmit(payload: {
 	body: string;
 	status: 'DRAFT' | 'PUBLISHED';
 	personIds: string[];
-	documentIds: string[];
 }) {
 	submitting = true;
 	errorMessage = null;
@@ -58,7 +57,6 @@ async function handleSubmit(payload: {
 
 	<GeschichteEditor
 		initialPersons={data.initialPersons}
-		initialDocuments={data.initialDocuments}
 		onSubmit={handleSubmit}
 		submitting={submitting}
 	/>