refactor(web): unify settings dialogs into single dialog with sidebar

Merge API integration, model settings, account settings and storage
analysis into one SettingsDialog with a shadcn inner sidebar for
section switching. Preserve existing ?action= query-param deep links
(showModelSettings / showAccountSettings / showApiIntegrationSettings /
showStorageAnalysis) by mapping each to a section. Extract reusable
panels and keep ModelsDialog as a thin wrapper for the dynamic-form
model picker.

web/src/i18n/locales/vi-VN.ts

@@ -1388,6 +1388,9 @@ const viVN = {
     boxSessionCreated: 'Đã tạo',
     boxSessionLastUsed: 'Lần cuối sử dụng',
   },
+  settingsDialog: {
+    title: 'Cài đặt',
+  },
   storageAnalysis: {
     title: 'Phân tích lưu trữ',
     description: 'Kiểm tra dung lượng lưu trữ và các mục có thể dọn dẹp',