feat: add OpenInsider Top-of-day crawler and multi-CRAWLER_TYPE support

New crawler: app/crawlers/openinsider_top.py\n- Scrapes three pages (sales/purchases/officer purchases)\n- Filters rows with Value/Amount >= ,000,000 (configurable via INSIDER_MIN_AMOUNT)\n- Builds concise notifications; saves to data/openinsider_top.json

Runner: support comma-separated CRAWLER_TYPE and new openinsider_top type\n- Accepts e.g., CRAWLER_TYPE=openinsider_top,openinsider,barrons\n- Preserves order, removes duplicates; warns on unknown types\n- Uses shared schedule: RUN_DAILY_AT or CHECK_INTERVAL; initial run per crawler

Entrypoint: rename enhanced_crawler.py -> main.py\n- Update Dockerfile CMD and README references

Config & docs:\n- Reorganize .env.template into clear sections with examples\n- Update .env with multi-crawler example and INSIDER_MIN_AMOUNT\n- README: document new crawler, usage, and multi-type CRAWLER_TYPE

main.py

@@ -0,0 +1,13 @@
+"""Entry point.
+
+The project has been refactored to separate API and crawler logic.
+This script delegates to the modular runner to keep Docker and
+local commands straightforward.
+"""
+
+from app.runner import start
+
+
+if __name__ == "__main__":
+    start()
+