refactor: modularize project structure and separate API from crawlers

- Introduce app/ package with config, services (storage, notifications), API server, and crawler modules
- Add BaseCrawler and BarronsCrawler; extract notifications and storage
- Keep enhanced_crawler.py as back-compat entry delegating to app.runner
- Add template crawler for future sites
- Update README with new structure and usage
- Extend .env.template with DATA_DIR/LOG_DIR options

app/runner.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+import threading
+
+from app.config import load_config, setup_logging
+from app.crawlers.barrons import BarronsCrawler
+from app.api.server import create_app
+
+
+def start():
+    # Load configuration and setup logging
+    config = load_config()
+    logger = setup_logging(config.log_level, config.log_dir)
+
+    # Create crawler instance
+    crawler = BarronsCrawler(config, logger)
+
+    # Create and start API in background
+    app = create_app(crawler)
+
+    def run_api():
+        app.run(host='0.0.0.0', port=8080, debug=False)
+
+    flask_thread = threading.Thread(target=run_api, daemon=True)
+    flask_thread.start()
+
+    # Run crawler loop (blocking)
+    crawler.run()
+