feat: scaffold travel-memories Flask app and test infrastructure

Adds services/travel-memories/ with Flask factory (create_app), stub
route blueprints, pytest/playwright smoke test infra (httpserver session
fix, pytest.ini pythonpath), phase2–6 fixture JSONs, Dockerfile, and
docker-compose service entry. Smoke test (test_health) passes.

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

.gitignore

@@ -19,5 +19,8 @@ test-results/
 playwright-report/
 tests/.auth/
 
+# travel-memories state
+docs/immich-workflow/*.json
+
 # OS
 .DS_Store