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",
 ]

app/models/alert.py

@@ -0,0 +1,32 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, Float, Index, String
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.database import Base
+
+
+class AlertLog(Base):
+    """Append-only log of alerts sent (and score watermarks).
+
+    Two uses, distinguished by ``alert_type``:
+      - notification dedup: a row records that ``dedup_key`` was alerted at
+        ``created_at``; the dispatcher suppresses re-sending the same key within
+        a cooldown window.
+      - score watermark: rows of type ``score_watermark`` carry the last
+        observed composite in ``value``; the latest row per key is the baseline
+        for score-deterioration alerts.
+    """
+
+    __tablename__ = "alert_log"
+    __table_args__ = (
+        Index("ix_alert_log_type_key_created", "alert_type", "dedup_key", "created_at"),
+    )
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    alert_type: Mapped[str] = mapped_column(String(30), nullable=False)
+    dedup_key: Mapped[str] = mapped_column(String(200), nullable=False)
+    value: Mapped[float | None] = mapped_column(Float, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=datetime.utcnow, nullable=False
+    )