feat: CI pipeline improvements

- remove image build duplication
- update workflows to use caching

.gitea/workflows/ci.yml

@@ -36,15 +36,10 @@ jobs:
         with:
           go-version: "1.22"
           cache: true
-          cache-dependency-path: |
-            backend/playout/go.sum
-            backend/chat/go.sum
+          cache-dependency-path: backend/chat/go.sum
 
-      - name: Validate Playlist Normalization
-        run: cd backend/playout && go run src/playlist.go playlist.txt || echo "Validation script not yet complete"
-
-      - name: Build Docker Images
-        run: docker compose build --no-cache
+      - name: Download Go modules
+        run: cd backend/chat && go mod download
 
       - name: Run Tests
         run: echo "Tests will be added in future CI steps (per TODO.md)"
@@ -89,6 +84,8 @@ jobs:
           push: true
           tags: ${{ steps.meta-playout.outputs.tags }}
           labels: ${{ steps.meta-playout.outputs.labels }}
+          cache-from: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:playout
+          cache-to: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:playout,mode=max
 
       - name: Extract metadata for Chat
         id: meta-chat
@@ -109,6 +106,8 @@ jobs:
           push: true
           tags: ${{ steps.meta-chat.outputs.tags }}
           labels: ${{ steps.meta-chat.outputs.labels }}
+          cache-from: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:chat
+          cache-to: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:chat,mode=max
 
       - name: Extract metadata for Nginx
         id: meta-nginx
@@ -123,23 +122,15 @@ jobs:
             type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push Nginx image
-        run: |
-          TAGS="${{ steps.meta-nginx.outputs.tags }}"
-          LABELS="${{ steps.meta-nginx.outputs.labels }}"
-          TAG_ARGS=""
-          for tag in $TAGS; do
-            TAG_ARGS="$TAG_ARGS --tag $tag"
-          done
-          LABEL_ARGS=""
-          while IFS= read -r label; do
-            [ -n "$label" ] && LABEL_ARGS="$LABEL_ARGS --label $label"
-          done <<< "$LABELS"
-          docker buildx build \
-            --push \
-            --file infrastructure/nginx/Dockerfile \
-            $TAG_ARGS \
-            $LABEL_ARGS \
-            .
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: infrastructure/nginx/Dockerfile
+          push: true
+          tags: ${{ steps.meta-nginx.outputs.tags }}
+          labels: ${{ steps.meta-nginx.outputs.labels }}
+          cache-from: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:nginx
+          cache-to: type=registry,ref=git.allucanget.biz/zwitschi/linearvoid/buildcache:nginx,mode=max
 
   release:
     needs: docker