feat: Phase 1 album selection with resume/start-over

Implements GET / listing Immich albums with resume badge, POST /select
creating TripState and redirecting to /triage; graceful error display
when Immich is unreachable.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/travel-memories/tests/test_phase1.py

@@ -0,0 +1,30 @@
+def test_album_list_renders(base_url, page):
+    page.goto(base_url)
+    assert page.locator(".album-card").count() == 1
+    assert "Central Asia 2023" in page.inner_text(".album-card")
+
+
+def test_select_single_album_creates_state(base_url, page):
+    page.goto(base_url)
+    page.locator(".album-card input[type=checkbox]").first.check()
+    page.fill("#grav-slug", "central-asia-2023")
+    page.locator("button[type=submit]").click()
+    page.wait_for_url("**/triage**")
+    assert "album_id=album-1" in page.url
+
+
+def test_resume_prompt_shown_for_existing_state(base_url, page, seed_state):
+    seed_state("phase2_state")
+    page.goto(base_url)
+    assert page.locator("[data-album-id=album-1] .resume-badge").is_visible()
+
+
+def test_immich_unreachable_shows_error(base_url, page, monkeypatch):
+    import app.routes.albums as a
+    orig = a.ImmichClient
+    class BrokenClient:
+        def __init__(self, *a, **k): pass
+        def list_albums(self): raise ConnectionError("down")
+    monkeypatch.setattr(a, "ImmichClient", BrokenClient)
+    page.goto(base_url)
+    assert page.locator(".alert-error").is_visible()