fix(ci): replace Google Cloud auth with Firebase token in prod workflow

- Remove google-github-actions/auth@v2 step that was failing
- Use --token with FIREBASE_TOKEN secret for Firebase deployments (same as staging)
- Aligns production workflow authentication with working staging workflow
- Resolves 'must specify exactly one of workload_identity_provider or credentials_json' error

This matches the authentication pattern used in deploy-staging.yml

Author: MrCoder

.github/workflows/deploy-prod.yml

@@ -25,13 +25,8 @@ jobs:
           node-version: ${{ matrix.node-version }}
       - run: yarn install && yarn build
       - run: yarn release
-      - name: Authenticate with Google Cloud
-        uses: google-github-actions/auth@v2
-        with:
-          credentials_json: ${{ secrets.GOOGLE_APPLICATION_CREDENTIALS }}
-
-      - run: cd functions && yarn install && yarn deploy:config:prod
-      - run: yarn deploy:prod
+      - run: cd functions && yarn install && yarn deploy:config:prod --token ${{ secrets.FIREBASE_TOKEN }}
+      - run: yarn deploy:prod --token ${{ secrets.FIREBASE_TOKEN }}
       - name: Upload Release Asset
         id: upload-release-asset
         uses: shogo82148/actions-upload-release-asset@v1