feat(web): migrate application shell to TanStack Start

- replace the legacy client-only Vite bootstrap with TanStack Router routes, Start SSR, and Nitro output

- compose the reusable layout, navigation, appearance, chats, and notifications blocks with application-owned data

- persist UI preferences through server functions and initialize theme, sidebar, and breakpoint state before hydration

- add React Query, hotkey, toaster, and responsive dashboard integration

- add application-owned Lingui configuration and catalogs, mount the runtime provider, and lazily enable I18nDevtool in development

- remove superseded HTML, main entry, theme provider, and application ESLint configuration

apps/web/i18n.config.json

@@ -0,0 +1,7 @@
+{
+  "sourceLocale": "en",
+  "locales": ["en", "zh-Hans"],
+  "catalogPath": "src/locales/{locale}/messages",
+  "include": ["src", "../../packages/blocks/src", "../../packages/ui/src"],
+  "exclude": ["**/*.test.{ts,tsx}", "**/node_modules/**"]
+}