fix(proxy): wait for server shutdown before exiting app

The previous cleanup logic only sent a shutdown signal but didn't wait
for the proxy server to actually stop. This caused a race condition
where the app would exit before cleanup completed, leaving Live configs
in an inconsistent state.

Changes:
- Add `server_handle` field to ProxyServer to track the spawned task
- Modify `stop()` to wait for server task completion (5s timeout)
- Add 100ms delay before process exit to ensure I/O flush
- Export ProxyService and fix test files that were missing proxy_service field

src-tauri/tests/support.rs

@@ -1,7 +1,7 @@
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex, OnceLock};
 
-use cc_switch_lib::{update_settings, AppSettings, AppState, Database, MultiAppConfig};
+use cc_switch_lib::{update_settings, AppSettings, AppState, Database, MultiAppConfig, ProxyService};
 
 /// 为测试设置隔离的 HOME 目录，避免污染真实用户数据。
 pub fn ensure_test_home() -> &'static Path {
@@ -48,15 +48,17 @@ pub fn test_mutex() -> &'static Mutex<()> {
 
 /// 创建测试用的 AppState，包含一个空的数据库
 pub fn create_test_state() -> Result<AppState, Box<dyn std::error::Error>> {
-    let db = Database::init()?;
-    Ok(AppState { db: Arc::new(db) })
+    let db = Arc::new(Database::init()?);
+    let proxy_service = ProxyService::new(db.clone());
+    Ok(AppState { db, proxy_service })
 }
 
 /// 创建测试用的 AppState，并从 MultiAppConfig 迁移数据
 pub fn create_test_state_with_config(
     config: &MultiAppConfig,
 ) -> Result<AppState, Box<dyn std::error::Error>> {
-    let db = Database::init()?;
+    let db = Arc::new(Database::init()?);
     db.migrate_from_json(config)?;
-    Ok(AppState { db: Arc::new(db) })
+    let proxy_service = ProxyService::new(db.clone());
+    Ok(AppState { db, proxy_service })
 }