refactor(chat): remove legacy screen visibility events and use absolute state refs

- Remove ChatScreenVisible and ChatScreenInvisible events from chat state machine
- Remove legacy ChatInit event handler
- Migrate state transitions to use absolute references (#chat.guestSession, #chat.userSession, #chat.idle)
- Adjust legal text wording for Cozsweet privacy agreement

src/app/auth/components/auth-legal-text.tsx

@@ -32,14 +32,14 @@ export function AuthLegalText() {
         {checked ? <span className={styles.checkboxInner} /> : null}
       </button>
       <p className={styles.text}>
-        I agree to the{" "}
+        I agree to the Cozsweet {" "}
         <a
           href={AppConstants.privacyPolicyUrl}
           className={styles.link}
           target="_blank"
           rel="noreferrer"
         >
-          Cozsweet Privacy Agreement
+          Privacy Agreement
         </a>{" "}
         and{" "}
         <a

src/app/chat/components/chat-screen.tsx

@@ -96,10 +96,8 @@ export function ChatScreen() {
   // 屏幕生命周期 + 派初次鉴权生命周期事件
   // ─────────────────────────────────────────────────────────────
   useEffect(() => {
-    chatDispatch({ type: "ChatScreenVisible" });
     dispatchAuthLifecycle(authState.loginStatus, chatDispatch);
     return () => {
-      chatDispatch({ type: "ChatScreenInvisible" });
     };
     // 注：mount useEffect 故意**不**依赖 loginStatus —— 首次 mount 时机是固定的
     //     （"用户进 /chat 那一刻"），loginStatus 由 splash/auth-screen 提前 settle。

src/stores/chat/chat-events.ts

@@ -18,8 +18,6 @@
 export type ChatEvent =
   // 内部 UI 事件
   | { type: "ChatInit" }
-  | { type: "ChatScreenVisible" }
-  | { type: "ChatScreenInvisible" }
   // 鉴权生命周期（**用户**显式触发登录后由 chat-screen 派）
   | { type: "ChatGuestLogin" }
   | { type: "ChatNonGuestLogin"; token: string }

src/stores/chat/chat-machine.ts

@@ -297,10 +297,8 @@ export const chatMachine = setup({
     // ─────────────────────────────────────────────────────────────
     idle: {
       on: {
-        ChatGuestLogin: "guestSession",
-        ChatNonGuestLogin: "userSession",
-        // 兼容旧事件（**无**资源 —— 旧 chat-screen 还在派 ChatInit）
-        ChatInit: "guestSession",
+        ChatGuestLogin: "#chat.guestSession",
+        ChatNonGuestLogin: "#chat.userSession",
         ChatLoadMoreHistory: "loadingMoreHistory", // 旧逻辑保留（翻历史用）
       },
     },
@@ -345,10 +343,9 @@ export const chatMachine = setup({
               actions: "appendUserImage",
             },
             ChatLoadMoreHistory: "loadingMore",
-            ChatScreenInvisible: "idle", // 屏不可见 → idle
-            ChatLogout: "idle", // 登出 → idle
+            ChatLogout: "#chat.idle", // 登出 → idle
             // 跨态（游客 → email）
-            ChatNonGuestLogin: "userSession",
+            ChatNonGuestLogin: "#chat.userSession",
             ChatAISentenceReceived: {
               actions: "appendOrUpdateAISentence",
             },
@@ -426,10 +423,9 @@ export const chatMachine = setup({
               actions: "appendUserImage",
             },
             ChatLoadMoreHistory: "loadingMore",
-            ChatScreenInvisible: "idle", // 屏不可见 → idle（cleanup WS via parent state exit）
-            ChatLogout: "idle", // 登出 → idle（cleanup WS）
+            ChatLogout: "#chat.idle", // 登出 → idle（cleanup WS）
             // 跨态（email → 游客）
-            ChatGuestLogin: "guestSession",
+            ChatGuestLogin: "#chat.guestSession",
             ChatAISentenceReceived: {
               actions: "appendOrUpdateAISentence",
             },
@@ -501,10 +497,9 @@ export const chatMachine = setup({
           actions: "appendUserImage",
         },
         ChatLoadMoreHistory: "loadingMoreHistory",
-        ChatScreenInvisible: "idle",
-        ChatLogout: "idle",
-        ChatGuestLogin: "guestSession",
-        ChatNonGuestLogin: "userSession",
+        ChatLogout: "#chat.idle",
+        ChatGuestLogin: "#chat.guestSession",
+        ChatNonGuestLogin: "#chat.userSession",
         ChatAISentenceReceived: {
           actions: "appendOrUpdateAISentence",
         },