fix: replace GitHub Actions cache with registry cache for Gitea compatibility

GitHub Actions cache (type=gha) is not available in Gitea, causing timeout errors.
Replaced with registry-based cache which works with any container registry.

Changes:
- Backend: cache-from/to type=registry,ref=backend:buildcache
- Frontend: cache-from/to type=registry,ref=frontend:buildcache
- Removed debug step that's no longer needed

This allows Docker layer caching while maintaining Gitea compatibility.
Images are successfully being pushed to rg.fr-par.scw.cloud/weworkstudio

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/ci.yml

@@ -32,20 +32,6 @@ jobs:
       - name: Install dependencies
         run: npm install --legacy-peer-deps
 
-      - name: Debug - Check TypeScript config
-        run: |
-          echo "=== TypeScript Config ==="
-          cat tsconfig.json
-          echo ""
-          echo "=== TypeScript Build Config ==="
-          cat tsconfig.build.json
-          echo ""
-          echo "=== NestJS CLI Config ==="
-          cat nest-cli.json
-          echo ""
-          echo "=== Checking if domain files exist ==="
-          ls -la src/domain/ports/out/ | head -10
-
       - name: Lint code
         run: npm run lint
 
@@ -86,8 +72,8 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/backend:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/backend:buildcache,mode=max
           platforms: linux/amd64
 
   # ============================================
@@ -158,8 +144,8 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/frontend:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/frontend:buildcache,mode=max
           platforms: linux/amd64
           build-args: |
             NEXT_PUBLIC_API_URL=${{ secrets.NEXT_PUBLIC_API_URL || 'http://localhost:4000' }}