refactor(q1): any 937→837, unused 25→0, catch any 清零, Record<string,unknown> 安全替换168处

- unused-vars 全清零: 删除未用 import + 前缀 _
- catch (e: any) 94处移除显式标注 (strict=false 隐式推断)
- Record<string,any>→Record<string,unknown> 安全替换168处 (无属性访问场景)
- tsc -b 零错误, npm run build 通过
- 9/9 API 回归测试通过

frontend/src/components/auth/Login.tsx

@@ -89,7 +89,7 @@ export function Login() {
       useUserStore.getState().login(result.user, result.token, result.permissions ?? null);
       localStorage.setItem('token', result.token);
       navigate('/', { replace: true });
-    } catch (err: any) {
+    } catch (err) {
       const message = err instanceof Error ? (err as Record<string, any>).message : '登录失败，请检查用户名和密码';
       setError(message);
     } finally {