fix(ci): use direct docker login for Gitea registry (CAR-994)

docker/login-action@v3 exits 1 against git.farh.net. Replace with a
direct docker login shell command using secrets.REGISTRY_TOKEN via
--password-stdin.

cc @cpfarhood

.gitea/workflows/ci.yml

@@ -43,11 +43,7 @@ jobs:
           echo "version=$VERSION" >> "$GITHUB_OUTPUT"
 
       - name: Log in to Gitea Container Registry
-        uses: docker/login-action@v3
+        run: echo "${{ secrets.REGISTRY_TOKEN }}" | docker login ${{ env.REGISTRY }} -u "${{ github.actor }}" --password-stdin
-        with:
-          registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.REGISTRY_TOKEN }}
 
       - name: Extract metadata
         id: meta