fix(qa-group): recreate missing notes on unchanged sync

中文: 修复 QA Group 在本地 state 与正文 hash 看起来未变化时，如果 Anki 中对应 note 已丢失却不会自动补建的问题。现在同步会先校验 note 是否仍存在，缺失时自动重建并重写 GI。

English: Fix QA Group sync so missing Anki notes are recreated even when local state and block hashes look unchanged. Sync now verifies note existence first and self-heals by rebuilding the note and rewriting GI when needed.

src/application/services/QaGroupSyncService.test.ts

@@ -141,6 +141,48 @@ describe("QaGroupSyncService", () => {
     expect(result.syncedGroupBlocks[0]?.groupId).toBe("group-1");
     expect(result.syncedGroupBlocks[0]?.noteId).toBeDefined();
   });
+
+  it("recreates a missing QA Group note even when the local state looks unchanged", async () => {
+    const ankiGateway = new FakeManualSyncAnkiGateway();
+    const vaultGateway = new FakeManualSyncVaultGateway();
+    const existingState = createStoredGroupBlockState();
+    const service = new QaGroupSyncService(
+      ankiGateway,
+      undefined,
+      undefined,
+      undefined,
+      () => 1234,
+      () => "group-x",
+      () => "item-new",
+      vaultGateway.createBacklink.bind(vaultGateway),
+    );
+
+    const result = await service.sync([
+      createIndexedGroupBlock({
+        noteId: 42,
+        groupId: "group-1",
+        rawBlockHash: existingState.rawBlockHash,
+        items: existingState.items.map(({ title, answer, ordinalInMarkdown }) => ({ title, answer, ordinalInMarkdown })),
+      }),
+    ], {
+      ...createEmptyPluginState(),
+      groupBlocks: {
+        "group-1": existingState,
+      },
+    }, createModule3Settings());
+
+    expect(result.created).toBe(1);
+    expect(result.updated).toBe(0);
+    expect(result.touchedSyncKeys).toContain("notes/example.md\u0000group\u00001\u0000hash-1");
+    expect(ankiGateway.addedNotes).toHaveLength(1);
+    expect(ankiGateway.addedNotes[0]?.fields).toMatchObject({
+      GroupId: "group-1",
+      S01_Q: "Alpha",
+      S03_Q: "Beta",
+    });
+    expect(result.markerWrites[0]?.noteId).toBe(result.syncedGroupBlocks[0]?.noteId);
+    expect(result.syncedGroupBlocks[0]?.noteId).not.toBe(42);
+  });
 });
 
 function createIndexedGroupBlock(overrides: Partial<IndexedGroupCardBlock> = {}): IndexedGroupCardBlock {

src/application/services/QaGroupSyncService.ts

@@ -132,21 +132,19 @@ export class QaGroupSyncService {
         let fieldsChanged = !stateUnchanged;
         let deckChanged = recovered.stateRecord ? recovered.stateRecord.deck !== deck : false;
 
-        if (!stateUnchanged) {
-          existingNote ??= await this.tryLoadQaGroupNote(noteId, block);
-          if (!existingNote) {
-            noteId = await this.ankiGateway.addNote({
-              deckName: deck,
-              modelName: QA_GROUP_MODEL_NAME,
-              fields,
-              tags: [],
-            });
-            created += 1;
-            touchedSyncKeys.add(block.syncKey);
-          } else {
-            fieldsChanged = !haveEqualFields(existingNote.fields, fields);
-            deckChanged = !(existingNote.deckNames ?? []).includes(deck);
-          }
+        existingNote ??= await this.tryLoadQaGroupNote(noteId, block);
+        if (!existingNote) {
+          noteId = await this.ankiGateway.addNote({
+            deckName: deck,
+            modelName: QA_GROUP_MODEL_NAME,
+            fields,
+            tags: [],
+          });
+          created += 1;
+          touchedSyncKeys.add(block.syncKey);
+        } else if (!stateUnchanged) {
+          fieldsChanged = !haveEqualFields(existingNote.fields, fields);
+          deckChanged = !(existingNote.deckNames ?? []).includes(deck);
         }
 
         if (existingNote && (fieldsChanged || deckChanged)) {