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

docs/md_v2/marketplace/backend/config.py

@@ -0,0 +1,59 @@
+"""
+Marketplace Configuration - Loads from .env file
+"""
+import os
+import sys
+import hashlib
+from pathlib import Path
+from dotenv import load_dotenv
+
+# Load .env file
+env_path = Path(__file__).parent / '.env'
+if not env_path.exists():
+    print("\n❌ ERROR: No .env file found!")
+    print("Please copy .env.example to .env and update with your values:")
+    print(f"  cp {Path(__file__).parent}/.env.example {Path(__file__).parent}/.env")
+    print("\nThen edit .env with your secure values.")
+    sys.exit(1)
+
+load_dotenv(env_path)
+
+# Required environment variables
+required_vars = ['MARKETPLACE_ADMIN_PASSWORD', 'MARKETPLACE_JWT_SECRET']
+missing_vars = [var for var in required_vars if not os.getenv(var)]
+
+if missing_vars:
+    print(f"\n❌ ERROR: Missing required environment variables: {', '.join(missing_vars)}")
+    print("Please check your .env file and ensure all required variables are set.")
+    sys.exit(1)
+
+class Config:
+    """Configuration loaded from environment variables"""
+
+    # Admin authentication - hashed from password in .env
+    ADMIN_PASSWORD_HASH = hashlib.sha256(
+        os.getenv('MARKETPLACE_ADMIN_PASSWORD').encode()
+    ).hexdigest()
+
+    # JWT secret for token generation
+    JWT_SECRET_KEY = os.getenv('MARKETPLACE_JWT_SECRET')
+
+    # Database path
+    DATABASE_PATH = os.getenv('MARKETPLACE_DB_PATH', './marketplace.db')
+
+    # Token expiry in hours
+    TOKEN_EXPIRY_HOURS = int(os.getenv('MARKETPLACE_TOKEN_EXPIRY', '4'))
+
+    # CORS origins - hardcoded as they don't contain secrets
+    ALLOWED_ORIGINS = [
+        "http://localhost:8000",
+        "http://localhost:8080",
+        "http://localhost:8100",
+        "http://127.0.0.1:8000",
+        "http://127.0.0.1:8080",
+        "http://127.0.0.1:8100",
+        "https://crawl4ai.com",
+        "https://www.crawl4ai.com",
+        "https://docs.crawl4ai.com",
+        "https://market.crawl4ai.com"
+    ]