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/services/admin_service.py

@@ -482,6 +482,7 @@ VALID_JOB_NAMES = {
     "rr_scanner",
     "ticker_universe_sync",
     "outcome_evaluator",
+    "alerts",
 }
 
 JOB_LABELS = {
@@ -491,6 +492,7 @@ JOB_LABELS = {
     "rr_scanner": "R:R Scanner",
     "ticker_universe_sync": "Ticker Universe Sync",
     "outcome_evaluator": "Outcome Evaluator",
+    "alerts": "Alerts Dispatcher",
 }