feat: add file-backed canvas notes

Magic Notes previously supported rich-text records without a paged drawing or
PDF annotation workflow. Add the integrated PeopleLib Fabric and Quill editor
with flowing text, pen/highlighter, object transforms, images, paper templates,
PDF backgrounds with native text extraction, and raster PDF export. Saves are
manual; undo/redo remains scoped to an annotation page or Quill mode.

Analyze drafts, saved canvases and canvas-source todos with page images and
text when the default model supports images, or an explicitly labelled
text-only fallback. Keep successful saves when automatic analysis fails and
prevent MCP plain-text replacement of canvas records.

Move entry bodies and binary assets into local note files with schema 38
migration and verified readback. SQLite retains metadata, indexes, revisions,
todos and comments. Backups must coordinate SQLite and the adjacent notes
directory while writes are paused or the app is closed; no one-click backup
action is included.

Show a continuous record stream with independent collapsible record index and
AI pane, real first-page thumbnails, and scroll-only record navigation. Open a
blank text/canvas composer by default and reset it after creation. Protect
unsaved drafts and establish normalized editor baselines after saving so clean
records do not prompt again when leaving.

Validation: latest recorded focused run passed 149 tests across five files;
typecheck, lint and git diff --check passed. The prior user-reported full run
passed 4,713 tests before later corrections and UI changes; it is not a full
validation of this final snapshot. Tests were not rerun for this commit, as
requested; independent systematic review follows the commit.

Release note: Create paged notes with handwriting, flowing text and PDF
annotations, browse records through thumbnails, and request AI comments with
an explicit text-only fallback. Existing notes migrate to local file storage;
backups now need both the database and notes directory.

src/main/assistant/assistant-database.test.ts

@@ -21,6 +21,47 @@ import type { ImageOperation } from '../../shared/image-generation-contracts'
 
 const temporaryDirectories: string[] = []
 
+it('roundtrips canvas assets and keeps todos stable across geometry edits and completion', async () => {
+  const database = await createDatabase()
+  try {
+    const content = {
+      version: 2 as const, kind: 'paged-canvas' as const,
+      pages: [{ id: 'page', width: 794, height: 1123,
+        background: { type: 'template' as const, template: 'grid' as const },
+        objects: [{ type: 'IText', text: 'Canvas annotation', left: 1 }] }],
+      flow: { version: 1 as const, ops: [{ insert: 'Canvas task' }, { insert: '\n', attributes: { list: 'unchecked' } }] },
+      assets: [{ id: 'file', name: 'file.txt', mimeType: 'text/plain', dataUrl: 'data:text/plain;base64,aGVsbG8=' }]
+    }
+    const note = database.createMagicNote({ title: 'Canvas', content })
+    const entry = note.entries[0]!
+    const todo = database.listMagicTodos()[0]!
+    database.saveMagicNoteAnalysis({ entryId: entry.id, expectedRevision: entry.revision, comments: [{ id: randomUUID(), kind: 'summary', content: 'Old analysis', inputMode: 'canvas-images' }] })
+    const analyzed = database.getMagicNoteEntry(entry.id)
+    const moved = { ...content, pages: [{ ...content.pages[0]!, objects: [{ type: 'IText', text: 'Canvas annotation', left: 500 }] }] }
+    database.updateMagicNoteEntry({ entryId: entry.id, content: moved, plainText: 'stale text', expectedRevision: analyzed.revision })
+    expect(database.getMagicNoteEntry(entry.id)).toMatchObject({ content: moved, plainText: 'Canvas task\nCanvas annotation', comments: [] })
+    expect(database.listMagicTodos()[0]).toMatchObject({ id: todo.id, sourceIndex: 0, revision: todo.revision })
+    database.updateMagicTodo({ todoId: todo.id, completed: true, expectedRevision: todo.revision })
+    const saved = database.getMagicNoteEntry(entry.id)
+    expect(saved.content).toMatchObject({ pages: moved.pages, assets: content.assets, flow: { ops: [{ insert: 'Canvas task' }, { insert: '\n', attributes: { list: 'checked' } }] } })
+    expect(() => database.updateMagicNoteEntry({ entryId: entry.id, content, plainText: '', expectedRevision: entry.revision })).toThrow('已被更新')
+    database.close()
+    database.initialize('C:\\Workspace')
+    expect(database.getMagicNoteEntry(entry.id)).toEqual(saved)
+    expect(database.searchMagicNotes('Canvas annotation', 10)).toHaveLength(1)
+    database.saveMagicNoteAnalysis({ entryId: entry.id, expectedRevision: saved.revision, comments: [{ id: randomUUID(), kind: 'summary', content: 'Text analysis', inputMode: 'text-fallback' }] })
+    const textAnalyzed = database.getMagicNoteEntry(entry.id)
+    const repositioned = { ...moved, pages: [{ ...moved.pages[0]!, objects: [{ type: 'IText', text: 'Canvas annotation', left: 200 }] }] }
+    database.updateMagicNoteEntry({ entryId: entry.id, content: repositioned, plainText: '', expectedRevision: textAnalyzed.revision })
+    const textPreserved = database.getMagicNoteEntry(entry.id)
+    expect(textPreserved.comments).toEqual(textAnalyzed.comments)
+    expect(textPreserved.analyzedAt).toEqual(textAnalyzed.analyzedAt)
+    const revised = { ...repositioned, pages: [{ ...repositioned.pages[0]!, objects: [{ type: 'IText', text: 'Changed annotation', left: 200 }] }] }
+    database.updateMagicNoteEntry({ entryId: entry.id, content: revised, plainText: '', expectedRevision: textPreserved.revision })
+    expect(database.getMagicNoteEntry(entry.id).comments).toEqual([])
+  } finally { database.close() }
+})
+
 it('persists conversation pins without changing timestamps or allowing autosaves to overwrite them', async () => {
   const database = await createDatabase()
   const header = { id: randomUUID(), title: 'Pinned conversation', updatedAt: 1000 }
@@ -100,7 +141,7 @@ it('migrates schema 35 conversations to unpinned while retaining existing data a
   }
   const inspected = new DatabaseSync(path)
   try {
-    expect(inspected.prepare('PRAGMA user_version').get()).toEqual({ user_version: 36 })
+    expect(inspected.prepare('PRAGMA user_version').get()).toEqual({ user_version: ASSISTANT_DATABASE_SCHEMA_VERSION })
     expect(inspected.prepare('PRAGMA integrity_check').get()).toEqual({ integrity_check: 'ok' })
     expect(inspected.prepare('SELECT created_at, updated_at FROM conversations WHERE id = ?').get(header.id)).toEqual({
       created_at: new Date(1000).toISOString(), updated_at: new Date(1000).toISOString()
@@ -1648,9 +1689,11 @@ describe('AssistantDatabase', () => {
       },
       plainText: '迁移待办'
     })
+    const legacyContent = initial.getMagicNote(note.id).entries[0]!.content
     initial.close()
 
     const legacy = new DatabaseSync(databasePath)
+    legacy.prepare('UPDATE magic_note_entries SET content_json = ? WHERE note_id = ?').run(JSON.stringify(legacyContent), note.id)
     legacy.exec(`
       DELETE FROM magic_todos;
       ALTER TABLE conversations DROP COLUMN pinned;
@@ -6773,9 +6816,8 @@ describe('AssistantDatabase', () => {
       completed: true,
       revision: todo.revision + 1
     })
-    expect(
-      database.getMagicNote(note.id).entries[0]!.content.ops
-    ).toEqual([
+    const updatedContent = database.getMagicNote(note.id).entries[0]!.content
+    expect(updatedContent.version === 1 && updatedContent.ops).toEqual([
       { insert: '核对发布材料' },
       { insert: '\n', attributes: { list: 'checked' } }
     ])