fix(anki): allow timing review cards without media

- Keep existing or create new cards without generating audio or images
- Refine timing review timeline expansion labels and boundary markers

src/core/services/ipc.test.ts

@@ -648,6 +648,28 @@ test('registerIpcHandlers exposes playback window activation request', async ()
   assert.deepEqual(calls, ['activate']);
 });
 
+test('registerIpcHandlers accepts the keep-without-media timing decision', async () => {
+  const { registrar, handlers } = createFakeIpcRegistrar();
+  const requests: unknown[] = [];
+  registerIpcHandlers(
+    createRegisterIpcDeps({
+      resolveMediaTimingReview: async (request) => {
+        requests.push(request);
+        return { ok: true };
+      },
+    }),
+    registrar,
+  );
+
+  const handler = handlers.handle.get(IPC_CHANNELS.request.mediaTimingReviewResolve);
+  assert.ok(handler);
+  assert.deepEqual(
+    await handler!({}, { reviewId: 'review-1', decision: { action: 'skip-media' } }),
+    { ok: true },
+  );
+  assert.deepEqual(requests, [{ reviewId: 'review-1', decision: { action: 'skip-media' } }]);
+});
+
 test('registerIpcHandlers forwards yomitan lookup tracking commands to immersion tracker', () => {
   const { registrar, handlers } = createFakeIpcRegistrar();
   const calls: string[] = [];

src/core/services/ipc.ts

@@ -275,7 +275,11 @@ function parseMediaTimingReviewResolveRequest(
   const decision = record.decision;
   if (!decision || typeof decision !== 'object') return null;
   const decisionRecord = decision as Record<string, unknown>;
-  if (decisionRecord.action === 'use-original' || decisionRecord.action === 'discard') {
+  if (
+    decisionRecord.action === 'use-original' ||
+    decisionRecord.action === 'skip-media' ||
+    decisionRecord.action === 'discard'
+  ) {
     return { reviewId: record.reviewId, decision: { action: decisionRecord.action } };
   }
   if (