style: remove markdown bold syntax from code comments

Remove `**...**` emphasis markers from inline comments and JSDoc blocks across
auth and chat components, machine mappers, and quota helpers. These are
plain code comments, not rendered markdown, so the bold syntax was noise.

Files touched:
- src/app/auth/components/auth-screen.tsx
- src/app/chat/components/chat-header.tsx
- src/app/chat/components/chat-screen.tsx
- chat machine mapper / quota helpers

No functional or behavioral changes.

src/core/net/interceptor/token_interceptor.ts

@@ -87,7 +87,7 @@ export const onRequestToken: FetchHook = async (ctx) => {
 
   const token = await getAuthToken();
   if (token) {
-    // ofetch 推荐：改 ctx.options.headers（**不**依赖 ctx.request 是 Request 实例 —— 实例类型不稳定）
+    // ofetch 推荐：改 ctx.options.headers（不依赖 ctx.request 是 Request 实例 —— 实例类型不稳定）
     const headers = new Headers(ctx.options.headers);
     headers.set("Authorization", `Bearer ${token}`);
     ctx.options.headers = headers;