fix: publish staging web with configured Supabase

.github/workflows/backend-quality-gate.yml

@@ -83,6 +83,24 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Validate staging web build variables
+        env:
+          STAGING_SUPABASE_URL: ${{ vars.STAGING_SUPABASE_URL }}
+          STAGING_SUPABASE_ANON_KEY: ${{ vars.STAGING_SUPABASE_ANON_KEY }}
+        run: |
+          test -n "$STAGING_SUPABASE_URL" || {
+            echo "STAGING_SUPABASE_URL is required" >&2
+            exit 1
+          }
+          test -n "$STAGING_SUPABASE_ANON_KEY" || {
+            echo "STAGING_SUPABASE_ANON_KEY is required" >&2
+            exit 1
+          }
+          if [[ ! "$STAGING_SUPABASE_URL" =~ ^https://[a-z0-9][a-z0-9-]*\.supabase\.co/?$ ]]; then
+            echo "STAGING_SUPABASE_URL must be an HTTPS Supabase project URL" >&2
+            exit 1
+          fi
+
       - name: Log in to GHCR
         uses: docker/login-action@v3
         with:
@@ -106,5 +124,5 @@ jobs:
           push: true
           tags: ghcr.io/jesse-ux/jyotisha-web:${{ github.sha }}
           build-args: |
-            NEXT_PUBLIC_SUPABASE_URL=https://placeholder.supabase.co
-            NEXT_PUBLIC_SUPABASE_ANON_KEY=placeholder
+            NEXT_PUBLIC_SUPABASE_URL=${{ vars.STAGING_SUPABASE_URL }}
+            NEXT_PUBLIC_SUPABASE_ANON_KEY=${{ vars.STAGING_SUPABASE_ANON_KEY }}