Add GitHub Actions step to validate Postmark credentials (#3)

* Initial plan

* Add separate step to check Postmark credentials in CI

Co-authored-by: sokripon <79755465+sokripon@users.noreply.github.com>

* Fix security issue: Use environment variables for credential check

Co-authored-by: sokripon <79755465+sokripon@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sokripon <79755465+sokripon@users.noreply.github.com>

Author: Copilot

.github/workflows/tests.yml

@@ -25,6 +25,21 @@ jobs:
       - name: Run linter
         run: uv run ruff check .
 
+      - name: Check Postmark credentials
+        env:
+          POSTMARK_API_TOKEN: ${{ secrets.POSTMARK_API_TOKEN }}
+          SENDER_EMAIL: ${{ secrets.SENDER_EMAIL }}
+        run: |
+          if [ -z "$POSTMARK_API_TOKEN" ]; then
+            echo "Error: POSTMARK_API_TOKEN is not set in repository secrets"
+            exit 1
+          fi
+          if [ -z "$SENDER_EMAIL" ]; then
+            echo "Error: SENDER_EMAIL is not set in repository secrets"
+            exit 1
+          fi
+          echo "Postmark credentials are properly configured"
+      
       - name: Run tests
         env:
           POSTMARK_API_TOKEN: ${{ secrets.POSTMARK_API_TOKEN }}