fix(bulk-edit): align BulkEditEntry shape with backend DocumentBatchSummary

Production bug — the backend serialises the document UUID as `id`, but
BulkEditEntry typed it as `documentId`. The runtime cast in /documents/
bulk-edit/+page.svelte was a TypeScript lie: every `entry.documentId`
became undefined, the SvelteMap collapsed all selections under the
undefined key, and the PATCH fired with `documentIds: []` (which the
controller correctly rejected with 400). Field semantics ACs could
therefore never fire end-to-end.

Renamed `BulkEditEntry.documentId` → `id`. The FileEntry built from each
summary still carries both `id` (local map key) and `documentId` (PATCH
payload) so the save handler is unchanged.

Reported by Elicit (B1) on PR #331.

Refs #225

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

frontend/src/lib/components/document/BulkDocumentEditLayout.svelte

@@ -20,8 +20,13 @@ import type { components } from '$lib/generated/api';
 
 type Person = components['schemas']['Person'];
 
+// Mirrors the backend `DocumentBatchSummary` JSON shape one-to-one — the route
+// passes the parsed `/api/documents/batch-metadata` response straight in, so
+// the field names must match what the backend actually serializes (id, not
+// documentId). The FileEntry built from each summary still uses both `id` and
+// `documentId` so the save handler can drive the PATCH payload by UUID.
 export type BulkEditEntry = {
-	documentId: string;
+	id: string;
 	title: string;
 	pdfUrl: string;
 };
@@ -71,15 +76,14 @@ let archiveFolder = $state('');
 // has already been resolved into `initialEditEntries`.
 if (mode === 'edit') {
 	for (const entry of untrack(() => initialEditEntries)) {
-		const id = entry.documentId; // reuse documentId as the local FileEntry key
-		files.set(id, {
-			id,
-			documentId: entry.documentId,
+		files.set(entry.id, {
+			id: entry.id,
+			documentId: entry.id,
 			title: entry.title,
 			status: 'idle',
 			previewUrl: entry.pdfUrl
 		});
-		if (!activeId) activeId = id;
+		if (!activeId) activeId = entry.id;
 	}
 }
 

frontend/src/lib/components/document/BulkDocumentEditLayout.svelte.spec.ts

@@ -317,7 +317,7 @@ describe('BulkDocumentEditLayout', () => {
 
 describe('BulkDocumentEditLayout — mode="edit"', () => {
 	const editEntry = (i: number) => ({
-		documentId: `doc-${i}`,
+		id: `doc-${i}`,
 		title: `Brief ${i}`,
 		pdfUrl: `/api/documents/doc-${i}/file`
 	});