Initial AlphaPulse implementation: news crawler and Binance klines

- Backend (FastAPI, SQLAlchemy 2, Alembic): single-admin cookie auth,
  news/crawler/market APIs with SSE and WebSocket streaming
- Crawler (Scrapy + Scrapy-Redis): wscn_news, wscn_live, cls_depth,
  cls_telegraph spiders, idempotent upserts with revisions, raw response
  archiving, per-source subprocess supervision, restart and backoff
- Market worker: full-history Binance spot/USD-M kline backfill,
  realtime WS stream, hourly and on-reconnect catch-up
- Frontend (Vue 3, Element Plus, UnoCSS, KLineChart): news feed,
  crawler console with live logs, Binance-style chart page
- Deploy: docker compose, nginx site, migrate and daily backup scripts

backend/.python-version

@@ -0,0 +1 @@
+3.13