fix: resolve CI pipeline failures for backend and frontend deploys

- Add Docker Buildx setup so GHA cache export works for backend image build
- Point SWA deploy app_location at the pre-built Angular output directory
  (skip_app_build validates app_location directly, not output_location)

Author: Piotr Stachaczynski

.github/workflows/deploy-backend.yml

@@ -21,6 +21,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Log in to GHCR
         uses: docker/login-action@v3
         with:

.github/workflows/deploy-frontend.yml

@@ -40,6 +40,5 @@ jobs:
           azure_static_web_apps_api_token: ${{ secrets.AZURE_STATIC_WEB_APPS_API_TOKEN }}
           repo_token: ${{ secrets.GITHUB_TOKEN }}
           action: upload
-          app_location: frontend
-          output_location: dist/frontend/browser
+          app_location: frontend/dist/frontend/browser
           skip_app_build: true