docs: 中性化 README 与代码注释中的第三方客户端引用

- README.md / README_EN.md：桌面 GUI 段落的第三方客户端类比改为中性的「托盘式桌面客户端」，功能说明不变
- cmd/gui 注释、internal/provider 注释：代理示例改为中性的本地 HTTP 代理表述
- internal/lua/plugins/channels.lua、internal/lua/vm.go：注释措辞中性化

仅文案与注释调整，无任何逻辑变更。

cmd/gui/main.js

@@ -1,5 +1,5 @@
 // ModelRouter Desktop GUI — main process
-// Clash-Verge-style: bundles and manages an embedded llmsproxy core instance
+// Tray-app style: bundles and manages an embedded llmsproxy core instance
 // in a per-user profile dir (userData), auto-starts it, keeps a tray icon,
 // supports launch-at-login. Server-side users keep using the pure Go binary.
 const {
@@ -215,7 +215,7 @@ function coreStarted() {
 function writeDefaultEmbeddedConfig() {
   // Generate a self-contained embedded profile with a fresh random admin key.
   // No upstream sources are preconfigured — the desktop user adds them via
-  // the WebUI's sources page (like Clash Verge's empty-by-default profile).
+  // the WebUI's sources page (like a desktop app's empty-by-default profile).
   // If a config already exists we do NOT overwrite it (keep user's edits).
   if (fs.existsSync(CONFIG_FILE)) return;
   const key = "sk-gw-" + crypto.randomBytes(16).toString("hex");
@@ -686,7 +686,7 @@ function createWindow() {
     });
   }
   // Silent start: `--silent` CLI flag or settings.silentStart keeps the app
-  // in the tray without showing the window (Clash-Verge style). First run
+  // in the tray without showing the window (tray-app style). First run
   // always shows the window so the user sees the dashboard.
   mainWindow.once("ready-to-show", () => {
     const firstRun = !fs.existsSync(