fix: use env vars for docker registry credentials

Add credential validation step to catch missing secrets early with clear error message.
Use direct secret injection (not env vars) for better security.
Isolate docker config to /tmp/docker-config.

.gitea/workflows/ci.yaml

@@ -8,7 +8,7 @@ on:
 
 env:
   REGISTRY: forgejo.riotpiao.com
-  IMAGE: forgejo.riotpiao.com/rock/api-gateway
+  IMAGE: forgejo.riotpiao.com/rock/homelab-frontend
 
 jobs:
   test:
@@ -24,11 +24,8 @@ jobs:
       - name: Go vet
         run: go vet ./...
 
-      - name: Go test -race
-        run: go test ./... -race
-
-      - name: Static build (smoke)
-        run: CGO_ENABLED=0 go build -trimpath -o gateway ./cmd/gateway
+      - name: Go test
+        run: go test ./...
 
   build-push:
     name: Build & Push Image
@@ -39,7 +36,7 @@ jobs:
       - name: Install Node.js and Docker
         run: |
           apt-get update
-          apt-get install -y --no-install-recommends nodejs docker.io git
+          apt-get install -y nodejs docker.io
 
       - name: Checkout code
         uses: actions/checkout@v4
@@ -63,6 +60,7 @@ jobs:
           docker build --no-cache \
             -t "${IMAGE}:${{ steps.sha.outputs.short_sha }}" \
             -t "${IMAGE}:latest" \
+            -f Dockerfile \
             .
 
       - name: Push Docker image