refactor(document): migrate frontend from DocumentSearchItem to flat DocumentListItem

All components, specs, and the generated API client now use the new
DocumentListItem shape — flat access (item.title, item.sender) instead of
the removed item.document.* nesting.

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

frontend/src/lib/document/DocumentRow.svelte.test.ts

@@ -20,10 +20,31 @@ const { default: DocumentRow } = await import('./DocumentRow.svelte');
 
 afterEach(cleanup);
 
-const sender = { id: 's1', displayName: 'Anna Schmidt' };
-const receiver = { id: 'r1', displayName: 'Bert Meier' };
+const sender = {
+	id: 's1',
+	lastName: 'Schmidt',
+	displayName: 'Anna Schmidt',
+	personType: 'PERSON' as const,
+	familyMember: false
+};
+const receiver = {
+	id: 'r1',
+	lastName: 'Meier',
+	displayName: 'Bert Meier',
+	personType: 'PERSON' as const,
+	familyMember: false
+};
 
-const makeDoc = (overrides: Record<string, unknown> = {}) => ({
+const emptyMatchData = {
+	titleOffsets: [],
+	senderMatched: false,
+	matchedReceiverIds: [],
+	matchedTagIds: [],
+	snippetOffsets: [],
+	summaryOffsets: []
+};
+
+const baseItem = (overrides: Record<string, unknown> = {}) => ({
 	id: 'd1',
 	title: 'Brief 1923',
 	originalFilename: 'b.pdf',
@@ -31,20 +52,14 @@ const makeDoc = (overrides: Record<string, unknown> = {}) => ({
 	sender,
 	receivers: [receiver],
 	tags: [],
-	thumbnailUrl: null,
-	contentType: 'application/pdf',
-	summary: null,
-	archiveBox: null,
-	archiveFolder: null,
-	location: null,
-	...overrides
-});
-
-const baseItem = (docOverrides: Record<string, unknown> = {}) => ({
-	document: makeDoc(docOverrides),
-	matchData: null,
+	summary: undefined,
+	archiveBox: undefined,
+	archiveFolder: undefined,
+	location: undefined,
+	matchData: emptyMatchData,
 	completionPercentage: 0,
-	contributors: []
+	contributors: [],
+	...overrides
 });
 
 describe('DocumentRow', () => {
@@ -121,12 +136,9 @@ describe('DocumentRow', () => {
 	it('renders the snippet when matchData provides a transcriptionSnippet', async () => {
 		render(DocumentRow, {
 			props: {
-				item: {
-					document: makeDoc(),
-					matchData: { transcriptionSnippet: 'Hello world snippet' },
-					completionPercentage: 50,
-					contributors: []
-				}
+				item: baseItem({
+					matchData: { ...emptyMatchData, transcriptionSnippet: 'Hello world snippet' }
+				})
 			}
 		});