Add unit tests for channel utilities and configure testing environment

- Created a new test file `channels.test.ts` to cover utilities related to channel configurations and targets.
- Implemented tests for normalizing and grouping selected channels by type, as well as building channel targets from account data and cron history.
- Mocked necessary dependencies to isolate tests and ensure accurate results.
- Updated `vite.config.ts` to set up the testing environment with jsdom and enable global variables for tests.

electron/main.ts

@@ -35,11 +35,6 @@ function refreshProviderRuntime(): { warnings: string[] } {
   }
 }
 
-function shouldPreferUpstreamHostApi(path: string, method: string): boolean {
-  const pathname = new URL(path, 'http://127.0.0.1').pathname;
-  return method.toUpperCase() === 'GET' && pathname === '/api/channels/targets';
-}
-
 async function requestUpstreamHostApi(path: string, method: string, headers: Record<string, string> | undefined, body: unknown) {
   const url = `${HOST_API_BASE_URL}${path}`;
   try {
@@ -81,13 +76,6 @@ async function requestUpstreamHostApi(path: string, method: string, headers: Rec
 ipcMain.handle('hostapi:fetch', async (_event, { path, method, headers, body }) => {
   const normalizedMethod = method || 'GET';
 
-  if (shouldPreferUpstreamHostApi(path, normalizedMethod)) {
-    const upstreamPreferred = await requestUpstreamHostApi(path, normalizedMethod, headers, body);
-    if (upstreamPreferred.success !== false && upstreamPreferred.ok !== false) {
-      return upstreamPreferred;
-    }
-  }
-
   // 1. 优先本地处理 Host API 路由（逐步对齐 ClawX）
   const localResult = await dispatchLocalHostApi({
     path,