test: end-to-end user journey in CI; fix ALS vectors for small libraries

- newApp (extracted from main) is the exact production wiring; the
  `ci / db` job now also runs it on PostgreSQL, Redis and Meilisearch
  and walks the main user flows over HTTP: first admin sign-in and
  credential change, local source and scan, search, album / artist /
  top tracks, signed stream, events and history, likes, fallback wave,
  playback state, upload queue up to review.
- ALS on a small library produced fewer than 64 factors and the insert
  into vector(64) failed; vectors are now zero-padded to the column size.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/ci-db.yml

@@ -1,5 +1,6 @@
 # Интеграционные проверки SQL на настоящем PostgreSQL + pgvector: миграции вверх / вниз / вверх,
-# запросы сканера, отпечатков, шаблонов и очереди (Go), загрузка каталога, профиля и обучение ALS (Python).
+# запросы сканера, отпечатков, шаблонов и очереди, сквозной сценарий пользователя через HTTP (Go),
+# загрузка каталога, профиля и обучение ALS (Python).
 name: ci / db
 
 on:
@@ -34,8 +35,18 @@ jobs:
           --health-interval 5s
           --health-timeout 5s
           --health-retries 20
+      redis:
+        image: redis:7.4-alpine
+      meilisearch:
+        image: getmeili/meilisearch:v1.11
+        env:
+          MEILI_MASTER_KEY: ci-master-key-0123456789
+          MEILI_ENV: development
     env:
       TEST_DATABASE_URL: postgres://pipu:pipu@postgres:5432/pipu?sslmode=disable
+      TEST_REDIS_URL: redis://redis:6379/0
+      TEST_MEILI_URL: http://meilisearch:7700
+      TEST_MEILI_KEY: ci-master-key-0123456789
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
@@ -43,6 +54,9 @@ jobs:
       - name: Go — миграции и запросы store
         working-directory: services/api
         run: go test -tags integration -count=1 -v ./internal/dbtest/
+      - name: Go — сквозной сценарий пользователя (newApp на Postgres, Redis, Meilisearch)
+        working-directory: services/api
+        run: go test -tags integration -count=1 -v -run TestUserJourney ./cmd/api/
       - uses: astral-sh/setup-uv@v6
         with: { version: "0.10.2", enable-cache: true, cache-dependency-glob: services/recommender/uv.lock }
       - name: Python — каталог, профиль, обучение ALS