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>

alembic/versions/005_add_alert_log.py

@@ -0,0 +1,40 @@
+"""add alert_log table
+
+Revision ID: 005
+Revises: 004
+Create Date: 2026-06-14 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "005"
+down_revision: Union[str, None] = "004"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "alert_log",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("alert_type", sa.String(length=30), nullable=False),
+        sa.Column("dedup_key", sa.String(length=200), nullable=False),
+        sa.Column("value", sa.Float(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(
+        "ix_alert_log_type_key_created",
+        "alert_log",
+        ["alert_type", "dedup_key", "created_at"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_alert_log_type_key_created", table_name="alert_log")
+    op.drop_table("alert_log")