feat(HRT-79): alertes Telegram configurables Premium/Pro

- telegram_alerts.py: service envoi alertes via Bot API (send_pre_race_alerts,
  build_race_alert, send_telegram_message) — gestion gracieuse TELEGRAM_BOT_TOKEN absent
- auth_db.py: migrate_telegram_columns() idempotente (ALTER TABLE + try/except OperationalError)
  colonnes: telegram_chat_id, alert_value_bets, alert_top1, alert_quinte_only
- api_v1/routes/user.py: blueprint user_bp GET/POST /api/v1/user/telegram-config
  protégé @jwt_required_middleware + @plan_required('premium','pro')
- api_v1/__init__.py: import + register user_bp
- turf_scheduler.py: run_telegram_alerts() + schedule_dynamic_telegram_alerts()
  planifiées 30min avant course (même pattern que schedule_dynamic_scoring)
  avec try/except Exception + fallback logger

Co-Authored-By: Paperclip <noreply@paperclip.ing>

auth_db.py

@@ -2,6 +2,7 @@
 """
 Auth DB — users and subscriptions schema for turf_saas.db
 Sprint 2-3: Auth JWT + Multi-tenant (HRT-28)
+HRT-79: migration Telegram columns
 """
 
 import sqlite3
@@ -63,6 +64,36 @@ def init_auth_tables():
     conn.close()
     print("[auth_db] Tables users, subscriptions, refresh_tokens created/verified.")
 
+    # Apply Telegram columns migration (idempotent)
+    migrate_telegram_columns()
+
+
+def migrate_telegram_columns():
+    """
+    Migration idempotente : ajoute les colonnes Telegram à la table users.
+    Utilise ALTER TABLE ... ADD COLUMN avec try/except OperationalError
+    pour être safe si les colonnes existent déjà (SQLite ne supporte pas IF NOT EXISTS).
+    HRT-79
+    """
+    conn = get_db()
+    c = conn.cursor()
+    columns = [
+        ("telegram_chat_id", "TEXT    DEFAULT NULL"),
+        ("alert_value_bets", "INTEGER DEFAULT 1"),
+        ("alert_top1", "INTEGER DEFAULT 1"),
+        ("alert_quinte_only", "INTEGER DEFAULT 0"),
+    ]
+    for col, definition in columns:
+        try:
+            c.execute(f"ALTER TABLE users ADD COLUMN {col} {definition}")
+            print(f"[auth_db] Colonne '{col}' ajoutée.")
+        except sqlite3.OperationalError:
+            # Column already exists — safe to ignore
+            pass
+    conn.commit()
+    conn.close()
+    print("[auth_db] Migration Telegram columns OK.")
+
 
 if __name__ == "__main__":
     init_auth_tables()