feat(ai): add dedicated digital avatar model config

backend/app/core/database.py

@@ -1,6 +1,7 @@
 """数据库连接管理"""
 import asyncio
 from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
+from sqlalchemy import text
 from sqlalchemy.orm import DeclarativeBase
 from app.core.config import settings
 from app.core.logger import logger
@@ -64,6 +65,18 @@ async def init_db():
             VirtualUser, UserPersonality, InteractionRecord,
             PendingReplyTask, TokenStat, AIModelConfig, SystemConfig, LoginLog
         )
+        async with engine.begin() as conn:
+            result = await conn.execute(text(
+                "SELECT COUNT(*) FROM information_schema.COLUMNS "
+                "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'ai_model_configs' "
+                "AND COLUMN_NAME = 'usage_scope'"
+            ))
+            if result.scalar_one() == 0:
+                await conn.execute(text(
+                    "ALTER TABLE ai_model_configs ADD COLUMN usage_scope "
+                    "VARCHAR(16) NOT NULL DEFAULT 'general' AFTER provider"
+                ))
+                logger.info("AI模型配置表已增加 usage_scope 字段")
         logger.info("✅ 数据库模型注册成功")
         logger.info("✅ 数据库初始化完成")