fix: clean up smart override when switching away from smart core

Refactor Smart kernel override management to always call manageSmartOverride.

src/main/core/manager.ts

@@ -160,9 +160,7 @@ async function prepareCore(detached: boolean, skipStop = false): Promise<CoreCon
   }
 
   // 管理 Smart 内核覆写配置
-  if (core === 'mihomo-smart') {
-    await manageSmartOverride()
-  }
+  await manageSmartOverride()
 
   // generateProfile 返回实际使用的 current
   const current = await generateProfile()