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>

frontend/src/pages/AdminPage.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react';
 import { ActivationSettings } from '../components/admin/ActivationSettings';
+import { AlertSettings } from '../components/admin/AlertSettings';
 import { SentimentProviderSettings } from '../components/admin/SentimentProviderSettings';
 import { DataCleanup } from '../components/admin/DataCleanup';
 import { JobControls } from '../components/admin/JobControls';
@@ -31,6 +32,7 @@ export default function AdminPage() {
         {activeTab === 'Settings' && (
           <div className="space-y-4">
             <ActivationSettings />
+            <AlertSettings />
             <SentimentProviderSettings />
             <TickerUniverseBootstrap />
             <RecommendationSettings />