fix(journey): paginate Immich picker and group photos by date

The /search route was looping up to 20 pages server-side, returning a
blob of up to 1000 photos with no hasMore flag, which prevented the
client's existing ScrollTrigger infinite scroll from ever firing.

Now the route proxies the client's page param directly to Immich and
returns a single page plus hasMore, enabling full library browsing.

The photo picker grid now groups photos by takenAt date (already
present in every asset response) with a date label above each group,
restoring the date-oriented browsing from V2. Closes #674.

server/tests/integration/memories-immich.test.ts

@@ -273,18 +273,19 @@ describe('Immich browse and search', () => {
     expect(res.body.buckets.length).toBeGreaterThan(0);
   });
 
-  it('IMMICH-042 — POST /search returns mapped assets', async () => {
+  it('IMMICH-042 — POST /search returns mapped assets with hasMore flag', async () => {
     const { user } = createUser(testDb);
     setImmichCredentials(testDb, user.id, 'https://immich.example.com', 'test-api-key');
 
     const res = await request(app)
       .post(`${IMMICH}/search`)
       .set('Cookie', authCookie(user.id))
-      .send({});
+      .send({ page: 1, size: 50 });
 
     expect(res.status).toBe(200);
     expect(Array.isArray(res.body.assets)).toBe(true);
     expect(res.body.assets[0]).toMatchObject({ id: 'asset-search-1', city: 'Paris', country: 'France' });
+    expect(typeof res.body.hasMore).toBe('boolean');
   });
 
   it('IMMICH-043 — POST /search when upstream throws returns 502', async () => {
@@ -611,43 +612,77 @@ describe('Immich syncAlbumAssets', () => {
 
 // ── searchPhotos pagination safety ────────────────────────────────────────────
 
-describe('Immich searchPhotos pagination safety', () => {
-  it('IMMICH-090 — searchPhotos stops at page 20 when hasMore is always true', async () => {
+describe('Immich searchPhotos pagination pass-through', () => {
+  it('IMMICH-090 — POST /search proxies client page param and returns hasMore', async () => {
     const { user } = createUser(testDb);
     setImmichCredentials(testDb, user.id, 'https://immich.example.com', 'test-api-key');
 
-    // Return a full page of 1000 items on every call, so the loop would
-    // run indefinitely without the page > 20 safety check.
+    // Return a full page so hasMore=true (items.length >= size)
     const fullPageResponse = {
       ok: true, status: 200,
       headers: { get: () => null },
       json: () => Promise.resolve({
         assets: {
-          items: Array.from({ length: 1000 }, (_, i) => ({
-            id: `asset-${i}`,
+          items: Array.from({ length: 50 }, (_, i) => ({
+            id: `asset-p2-${i}`,
             fileCreatedAt: '2024-06-01T10:00:00.000Z',
-            exifInfo: { city: 'Paris', country: 'France' },
+            exifInfo: { city: 'Berlin', country: 'Germany' },
           })),
         },
       }),
       body: null,
     } as any;
 
-    // Clear previous call history so the count only reflects this test
     vi.mocked(safeFetch).mockClear();
     vi.mocked(safeFetch).mockResolvedValue(fullPageResponse);
 
     const res = await request(app)
       .post(`${IMMICH}/search`)
       .set('Cookie', authCookie(user.id))
-      .send({});
+      .send({ page: 2, size: 50 });
 
     expect(res.status).toBe(200);
     expect(Array.isArray(res.body.assets)).toBe(true);
-    // 20 pages × 1000 items = 20000 assets total (safety limit)
-    expect(res.body.assets.length).toBe(20000);
-    // safeFetch should have been called exactly 20 times (the safety limit)
-    expect(vi.mocked(safeFetch)).toHaveBeenCalledTimes(20);
+    // Single page returned — not 20× aggregation
+    expect(res.body.assets.length).toBe(50);
+    expect(res.body.hasMore).toBe(true);
+    // Immich was called exactly once
+    expect(vi.mocked(safeFetch)).toHaveBeenCalledTimes(1);
+    // page=2 was forwarded to Immich
+    const callBody = JSON.parse(vi.mocked(safeFetch).mock.calls[0][1]!.body as string);
+    expect(callBody.page).toBe(2);
+  });
+
+  it('IMMICH-091 — POST /search returns hasMore=false on last page', async () => {
+    const { user } = createUser(testDb);
+    setImmichCredentials(testDb, user.id, 'https://immich.example.com', 'test-api-key');
+
+    // Partial page → hasMore=false
+    const partialPageResponse = {
+      ok: true, status: 200,
+      headers: { get: () => null },
+      json: () => Promise.resolve({
+        assets: {
+          items: Array.from({ length: 3 }, (_, i) => ({
+            id: `asset-last-${i}`,
+            fileCreatedAt: '2024-06-01T10:00:00.000Z',
+            exifInfo: { city: 'Rome', country: 'Italy' },
+          })),
+        },
+      }),
+      body: null,
+    } as any;
+
+    vi.mocked(safeFetch).mockResolvedValue(partialPageResponse);
+
+    const res = await request(app)
+      .post(`${IMMICH}/search`)
+      .set('Cookie', authCookie(user.id))
+      .send({ page: 5, size: 50 });
+
+    expect(res.status).toBe(200);
+    expect(res.body.assets.length).toBe(3);
+    expect(res.body.hasMore).toBe(false);
   });
 });