refactor(notes): remove legacy whole-document saves; all block changes go through sync

Phase 5 of the collaboration plan:
- Remove PATCH /documents/{id}/blocks, PatchDocumentBlocks, the
  DOC_BLOCKS_PATCHED event and its types, FlushDocumentState and
  LoadDocumentState. PUT /documents/{id} rejects blocks (400) and only
  changes title, icon, folder and pin; editors may now change title/icon.
- The to-do overview ticks via a single operation on /docs/{id}/sync
  (new skipLog flag). Task links set the block tick with a targeted
  operation and notify open editors; creating a linked task needs edit
  rights.
- Keep the three share tables: DocRole already decides centrally, and
  rewriting the visibility queries would only add risk (documented in plan).
- Tests adapted to the new paths; share e2e test now also ticks a to-do in
  the overview.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/workspace/WorkspaceView.tsx

@@ -49,6 +49,7 @@ import {
   RealtimeTransport,
 } from '../../lib/api';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
+import { sendDocOps } from '../../lib/docSync/oneoff';
 import { useMobileActions } from '../../context/MobileActionContext';
 import { DocumentEditor, DocSaveStatus } from './DocumentEditor';
 
@@ -789,9 +790,8 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
       prev.map((d) => (d.id === doc.id ? { ...d, blocks: updatedBlocks } : d))
     );
     try {
-      await api.patchDocumentBlocks(doc.id, {
-        upserted: [{ id: blockId, checked: !currentChecked, type: 'todo', content: '' }],
-      });
+      const [result] = await sendDocOps(doc.id, [{ kind: 'set_props', blockId, patch: { checked: !currentChecked } }]);
+      if (result?.status !== 'applied') loadWorkspaceData();
     } catch {
       loadWorkspaceData();
     }

frontend/src/lib/api.ts

@@ -595,11 +595,10 @@ export const api = {
       title?: string;
       icon?: string;
       folderPath?: string;
-      blocks?: DocumentBlock[];
-      tags?: string[];
       isPinned?: boolean;
     }
   ): Promise<Document> {
+    // Block content is saved through the note sync engine (lib/docSync), not here
     const d = await request<Document>(`/api/v1/documents/${id}`, {
       method: 'PUT',
       body: JSON.stringify(patch),
@@ -611,25 +610,6 @@ export const api = {
     };
   },
 
-  async patchDocumentBlocks(
-    id: string,
-    payload: {
-      upserted?: DocumentBlock[];
-      deletedIds?: string[];
-      blockOrder?: string[];
-    }
-  ): Promise<Document> {
-    const d = await request<Document>(`/api/v1/documents/${id}/blocks`, {
-      method: 'PATCH',
-      body: JSON.stringify(payload),
-    });
-    return {
-      ...d,
-      blocks: ensureArray(d.blocks),
-      tags: ensureArray(d.tags),
-    };
-  },
-
   async joinSSERoom(sseId: string, room: string, action: 'join' | 'leave' = 'join'): Promise<{ success: boolean }> {
     return request<{ success: boolean }>('/api/v1/events/rooms', {
       method: 'POST',

frontend/src/lib/docSync/oneoff.ts

@@ -0,0 +1,18 @@
+// Sends a few operations for a note that is not open in an editor (e.g. ticking a to-do in the overview).
+// Goes through the same sync endpoint and rules as the editor, so the change is logged and pushed to
+// everyone who has the note open.
+import type { Op, Result } from './model';
+import { httpTransport } from './transport';
+
+export async function sendDocOps(docId: string, ops: Omit<Op, 'opId'>[]): Promise<Result[]> {
+  const bytes = new Uint8Array(8);
+  crypto.getRandomValues(bytes);
+  const clientId = `once_${Array.from(bytes, (b) => b.toString(16).padStart(2, '0')).join('')}`;
+  const res = await httpTransport.sync(docId, {
+    clientId,
+    lastSeq: 0,
+    ops: ops.map((op, i) => ({ ...op, opId: `${clientId}.${i}` }) as Op),
+    skipLog: true,
+  });
+  return res.results;
+}

frontend/src/lib/docSync/transport.ts

@@ -37,6 +37,7 @@ export interface SyncRequest {
   lastSeq: number;
   ops: Op[];
   leases?: { hold: string[]; release: string[] };
+  skipLog?: boolean; // one-off changes do not need the log back
 }
 
 export interface SyncResponse {