feat(navigation): add profile stack navigator and fix API endpoints

- Add ProfileStackNavigatorComponent with full navigation stack (Profile, Settings, EditProfile, AccountSecurity, MyPosts, Bookmarks, NotificationSettings, BlockedUsers)
- Add null checks for response data in authService login, register, and refreshToken methods
- Fix postService API routes to use correct endpoints (/posts instead of /posts/cursor)
- Remove completed cursor pagination design document

src/navigation/SimpleMobileTabNavigator.tsx

@@ -40,8 +40,21 @@ export type ScheduleStackParamList = {
   CourseDetail: { course: any; relatedCourses?: any[] };
 };
 
+// Profile Stack 类型定义
+export type ProfileStackParamList = {
+  Profile: undefined;
+  Settings: undefined;
+  EditProfile: undefined;
+  AccountSecurity: undefined;
+  MyPosts: undefined;
+  Bookmarks: undefined;
+  NotificationSettings: undefined;
+  BlockedUsers: undefined;
+};
+
 // ==================== Stack Navigators ====================
 const ScheduleStack = createNativeStackNavigator<ScheduleStackParamList>();
+const ProfileStack = createNativeStackNavigator<ProfileStackParamList>();
 
 // ==================== 常量 ====================
 const TAB_BAR_HEIGHT = 64;
@@ -80,6 +93,84 @@ function ScheduleStackNavigatorComponent() {
   );
 }
 
+/**
+ * Profile Stack Navigator 组件
+ */
+function ProfileStackNavigatorComponent() {
+  return (
+    <ProfileStack.Navigator
+      screenOptions={{
+        headerStyle: {
+          backgroundColor: colors.background.paper,
+        },
+        headerTintColor: colors.text.primary,
+        headerTitleStyle: {
+          fontWeight: '600',
+        },
+        headerBackTitle: '',
+        headerShadowVisible: false,
+      }}
+    >
+      <ProfileStack.Screen
+        name="Profile"
+        component={ProfileScreen}
+        options={{
+          headerShown: false,
+        }}
+      />
+      <ProfileStack.Screen
+        name="Settings"
+        component={SettingsScreen}
+        options={{
+          title: '设置',
+        }}
+      />
+      <ProfileStack.Screen
+        name="EditProfile"
+        component={EditProfileScreen}
+        options={{
+          title: '编辑资料',
+        }}
+      />
+      <ProfileStack.Screen
+        name="AccountSecurity"
+        component={AccountSecurityScreen}
+        options={{
+          title: '账号安全',
+        }}
+      />
+      <ProfileStack.Screen
+        name="MyPosts"
+        component={ProfileScreen}
+        options={{
+          title: '我的帖子',
+        }}
+      />
+      <ProfileStack.Screen
+        name="Bookmarks"
+        component={ProfileScreen}
+        options={{
+          title: '收藏',
+        }}
+      />
+      <ProfileStack.Screen
+        name="NotificationSettings"
+        component={NotificationSettingsScreen}
+        options={{
+          title: '通知设置',
+        }}
+      />
+      <ProfileStack.Screen
+        name="BlockedUsers"
+        component={BlockedUsersScreen}
+        options={{
+          title: '黑名单',
+        }}
+      />
+    </ProfileStack.Navigator>
+  );
+}
+
 /**
  * 主组件：SimpleMobileTabNavigator
  */
@@ -108,7 +199,7 @@ export function SimpleMobileTabNavigator() {
       case 'ScheduleTab':
         return <ScheduleStackNavigatorComponent />;
       case 'ProfileTab':
-        return <ProfileScreen />;
+        return <ProfileStackNavigatorComponent />;
       default:
         return <HomeScreen />;
     }