refactor(chat): extract XState actors into chat-machine.actors.ts

- Split chat state machine actors (chatInit, sendMessageHttp, loadMoreHistory, chatWebSocket) into a dedicated module
- Add comprehensive console logging across the chat state machine for full trace debugging
- Comment out margin on text bubble CSS for layout adjustment
- Add debug logging to chat input bar send handler
- Clean up redundant comments in auth-screen component

src/stores/chat/chat-state.ts

@@ -9,6 +9,12 @@
  *     - 游客：chat-screen 派 `ChatInit` → readInitData 调 ChatStorage → onDone 条件赋
  *     - 非游客：**永不被赋值**（业务事实"非游客无消息限制"）—— 0 - 1 = max(0, -1) = 0 天然 no-op
  *     - 0 同时表示"未初始化"和"已耗尽" —— UI 用 `if (isGuest && ...)` 天然过滤
+ *
+ * 新增 `wsConnected: boolean`（**仅** userSession 期间 true）：
+ *   - **WS 已连** → 消息发送走 WS，**不**消耗次数
+ *   - **WS 未连** → 消息发送走 HTTP，消耗次数
+ *   - `ChatWebSocketConnected` 事件 → true
+ *   - `userSession.exit` → false（WS actor cleanup 时**也**会跑 exit）
  */
 import type { UiMessage } from "@/models/chat/ui-message";
 
@@ -16,7 +22,13 @@ export interface ChatState {
   messages: UiMessage[];
   isReplyingAI: boolean;
   /**
-   * 游客剩余配额（次/天）—— **仅**游客业务展示用
+   * WebSocket 连接状态（**仅** userSession 期间 true）
+   * - 决定消息发送**路径**（WS / HTTP）和**是否消耗**次数
+   * - true：走 WS，**不**消耗次数
+   * - false：走 HTTP，消耗次数
+   */
+  wsConnected: boolean;
+  /** 游客剩余配额（次/天）—— **仅**游客业务展示用
    * - default 0 = "未初始化" / "已耗尽"（同码，靠 `isGuest` 区分）
    * - 非游客：永不被赋值（业务事实"无消息限制"）
    */
@@ -32,6 +44,7 @@ export interface ChatState {
 export const initialState: ChatState = {
   messages: [],
   isReplyingAI: false,
+  wsConnected: false,
   guestRemainingQuota: 0,
   guestTotalQuota: 0,
   quotaExceededTrigger: 0,