feat(marketplace): Add Crawl4AI marketplace with secure configuration

- Implement marketplace frontend and admin dashboard
- Add FastAPI backend with environment-based configuration
- Use .env file for secrets management
- Include data generation scripts
- Add proper CORS configuration
- Remove hardcoded password from admin login
- Update gitignore for security

.gitignore

@@ -1,6 +1,13 @@
 # Scripts folder (private tools)
 .scripts/
 
+# Database files
+*.db
+
+# Environment files
+.env
+.env.local
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]