Rebrand the entire application from "胡萝卜社区" (Carrot BBS) to "威友" (WithYou), including:

- Update app name, package name (skin.carrot.bbs → cn.qczlit.withyou), and bundle identifier
- Update API endpoints (bbs.littlelan.cn → withyou.littlelan.cn)
- Update URL scheme (carrotbbs:// → withyou://)
- Rename database from carrot_bbs to with_you
- Update CI/CD pipeline image names and artifact naming
- Add Android signing configuration for release builds
- Update all UI text and comments throughout the codebase
- Refactor registerStore to use in-memory state instead of AsyncStorage persistence
- Improve WebRTC track handling and call stream management
- Add metro platform resolution for native platform support

BREAKING app package, database, and URLs are no longer valid

src/services/platform/apkUpdateService.ts

@@ -144,7 +144,7 @@ async function downloadAndInstallAPK(downloadUrl: string, version: string): Prom
   }
 
   try {
-    const downloadPath = `${FileSystem.documentDirectory}carrot-bbs-${version}.apk`;
+    const downloadPath = `${FileSystem.documentDirectory}with-you-${version}.apk`;
     
     // 显示下载进度
     showConfirm({