feat(web): add settings sub-pages and connect to backend APIs

- Add GeneralSettingsPage for language, privacy, and notification settings
- Add FeedbackPage for user feedback submission with image upload
- Connect settings to backend PATCH /users/me/settings API
- Implement language preference sync between frontend and backend
- Update login flow to pass language preference and redirect based on user settings
- Add Astro entry pages for /settings/general and /settings/feedback routes
- Update sidebar navigation: language button links to general settings
- Fix account data card to link to profile page
- Remove "deletion" text from account data description

web/src/lib/api-routes.ts

@@ -7,14 +7,25 @@ export const API_ROUTES = {
   },
   users: {
     profile: '/api/v1/users/me/profile',
+    updateProfile: '/api/v1/users/me/profile',
+    updateSettings: '/api/v1/users/me/settings',
+    avatarUploadUrl: '/api/v1/users/me/avatar/upload-url',
+    uploadAvatar: '/api/v1/users/me/avatar',
   },
   points: {
     balance: '/api/v1/points/balance',
+    packages: '/api/v1/points/packages',
   },
   notifications: {
+    list: '/api/v1/notifications',
     unreadCount: '/api/v1/notifications/unread-count',
+    markRead: (id: string) => `/api/v1/notifications/${id}/read`,
+    markAllRead: '/api/v1/notifications/mark-all-read',
   },
   agent: {
     history: '/api/v1/agent/history',
   },
+  feedback: {
+    submit: '/api/v1/feedback',
+  },
 } as const;