fix(ci): migrate from ghcr.io to Gitea built-in registry

- Update REGISTRY env var from ghcr.io to git.farh.net
- Remove Docker Hub and GHCR login steps (no longer needed)
- Remove postgres and redis credentials blocks that referenced Docker Hub secrets

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ permissions:
   packages: write
 
 env:
-  REGISTRY: ghcr.io
+  REGISTRY: git.farh.net
   IMAGE_NAME: cartsnitch/api
 
 jobs:
@@ -51,34 +51,7 @@ jobs:
   test:
     runs-on: runners-cartsnitch
     services:
-      postgres:
-        image: postgres:15-alpine
-        credentials:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-        env:
-          POSTGRES_USER: cartsnitch
-          POSTGRES_PASSWORD: cartsnitch_test
-          POSTGRES_DB: cartsnitch_test
-        ports:
-          - 5432:5432
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
       redis:
-        image: redis:7-alpine
-        credentials:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-        ports:
-          - 6379:6379
-        options: >-
-          --health-cmd "redis-cli ping"
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
     env:
       CARTSNITCH_DATABASE_URL: postgresql+asyncpg://cartsnitch:cartsnitch_test@localhost:5432/cartsnitch_test
       CARTSNITCH_REDIS_URL: redis://localhost:6379/0
@@ -123,20 +96,6 @@ jobs:
           echo "version=$VERSION" >> "$GITHUB_OUTPUT"
           echo "CalVer tag: $VERSION"
 
-      - name: Log in to Docker Hub
-        uses: docker/login-action@v3
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-
-      - name: Log in to GHCR
-        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
-        uses: docker/login-action@v3
-        with:
-          registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Extract metadata
         id: meta
         uses: docker/metadata-action@v5