fix: risklevel migration 自動化 + Telegram Whitelist 注入

1. init_db() 啟動時自動確保 risklevel enum 包含 'high' 值
   (Phase 23 新增，避免舊 DB 缺值導致 InvalidTextRepresentation)

2. CD Pipeline 新增 OPENCLAW_TG_USER_WHITELIST 自動注入
   (之前為 CHANGE_ME，已更新為實際 user ID 5619078117)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/db/base.py

@@ -16,6 +16,7 @@ Features:
 from collections.abc import AsyncGenerator
 from contextlib import asynccontextmanager
 
+from sqlalchemy import text
 from sqlalchemy.ext.asyncio import (
     AsyncEngine,
     AsyncSession,
@@ -145,6 +146,24 @@ async def init_db() -> None:
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)
 
+        # 2026-04-02 Claude Code: 確保 risklevel enum 包含 'high' 值
+        # Phase 23 新增，避免舊 DB 缺少此值導致 InvalidTextRepresentation
+        await conn.execute(
+            text("""
+            DO $$
+            BEGIN
+                IF NOT EXISTS (
+                    SELECT 1 FROM pg_enum
+                    WHERE enumtypid = 'risklevel'::regtype
+                      AND enumlabel = 'high'
+                ) THEN
+                    ALTER TYPE risklevel ADD VALUE 'high';
+                END IF;
+            END
+            $$;
+            """)
+        )
+
 
 async def close_db() -> None:
     """