add Telegram alerts: qualified setups, S/R proximity, score drops, daily digest

Closes the action loop — instead of polling the dashboard, the platform pushes
actionable signals to Telegram. New hourly 'alerts' job dispatches four
toggleable triggers, deduped via a new alert_log table (cooldown-based for
qualified/S-R/digest, watermark-based for score deterioration). Admin → Settings
gains a Telegram panel (write-only bot token, chat ID, per-trigger toggles, Send
Test). Credentials follow DB > env precedence (TELEGRAM_BOT_TOKEN / _CHAT_ID).

Backend: alert_service + AlertLog model + migration 005, scheduler job, admin
endpoints/schema. Frontend: AlertSettings panel, hooks, api, types.

Deploy: run alembic upgrade (new alert_log table).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/models/__init__.py

@@ -8,6 +8,7 @@ from app.models.sr_level import SRLevel
 from app.models.trade_setup import TradeSetup
 from app.models.watchlist import WatchlistEntry
 from app.models.settings import SystemSetting, IngestionProgress
+from app.models.alert import AlertLog
 
 __all__ = [
     "Ticker",
@@ -22,4 +23,5 @@ __all__ = [
     "WatchlistEntry",
     "SystemSetting",
     "IngestionProgress",
+    "AlertLog",
 ]