Fix malformed JSON secret files in Forgejo release workflow.

Write secrets via printf and validate with python json.tool so google-services and client secrets remain valid JSON in CI.

.forgejo/workflows/build_release.yml

@@ -68,18 +68,16 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          cat > app/google-services.json <<'EOF'
-          ${{ secrets.GOOGLE_SERVICES_JSON }}
-          EOF
+          printf '%s' "${{ secrets.GOOGLE_SERVICES_JSON }}" > app/google-services.json
+          python3 -m json.tool app/google-services.json > /dev/null
 
       - name: Write client_secrets.json
         shell: bash
         run: |
           set -euo pipefail
           mkdir -p app/src/main/assets
-          cat > app/src/main/assets/client_secrets.json <<'EOF'
-          ${{ secrets.GOOGLE_CLIENT_SECRETS_JSON }}
-          EOF
+          printf '%s' "${{ secrets.GOOGLE_CLIENT_SECRETS_JSON }}" > app/src/main/assets/client_secrets.json
+          python3 -m json.tool app/src/main/assets/client_secrets.json > /dev/null
 
       - name: Prepare release metadata
         id: prepare