Chore: Improve Docker deployment configuration

- Use environment variables in docker-compose for secrets/paths
- Add .env.example template for required variables
- Add .env to .gitignore to prevent secret exposure
- Add docker-build-and-push.cmd helper script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -34,3 +34,6 @@ packages/
 /MoneyMap/wwwroot/lib/
 /MoneyMap/wwwroot/receipts/
 **/publish/
+
+# Environment files with secrets
+.env