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/schemas/admin.py

@@ -77,3 +77,15 @@ class SentimentConfigUpdate(BaseModel):
 
 class SentimentTestRequest(BaseModel):
     ticker: str = Field(default="AAPL", max_length=10)
+
+
+class AlertConfigUpdate(BaseModel):
+    """Telegram alert config. bot_token is write-only; omit/empty to keep the
+    stored token."""
+    enabled: bool | None = None
+    bot_token: str | None = Field(default=None, max_length=200)
+    telegram_chat_id: str | None = Field(default=None, max_length=64)
+    qualified_enabled: bool | None = None
+    sr_proximity_enabled: bool | None = None
+    score_drop_enabled: bool | None = None
+    digest_enabled: bool | None = None