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- remove superseded HTML, main entry, theme provider, and application ESLint configuration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/src/styles/globals.css

@@ -0,0 +1,48 @@
+@import "@workspace/ui/globals.css";
+@import "@workspace/blocks/globals.css";
+
+:root {
+  --ui-content-top-gap: --spacing(2);
+  --ui-header-height: --spacing(18);
+  --ui-sidebar-collapsed-width: --spacing(22);
+  --ui-sidebar-width: --spacing(74);
+}
+
+.ui\:mobile {
+  --ui-header-height: --spacing(16);
+  --ui-sidebar-width: 0px;
+}
+
+.ui\:tablet,
+.ui\:collapsed:not(.ui\:mobile) {
+  --ui-sidebar-width: var(--ui-sidebar-collapsed-width);
+}
+
+.ui\:theme-changing *,
+.ui\:theme-changing *::before,
+.ui\:theme-changing *::after {
+  -webkit-transition: none !important;
+  transition: none !important;
+}
+
+@keyframes ui-show-scroll-divider {
+  from {
+    opacity: 0;
+  }
+
+  to {
+    opacity: 1;
+  }
+}
+
+@utility scroll-top-divider {
+  opacity: 0;
+}
+
+@supports (animation-timeline: scroll()) {
+  .scroll-top-divider {
+    animation: ui-show-scroll-divider 1s steps(1, end) both;
+    animation-range: 0px var(--ui-content-top-gap, 1px);
+    animation-timeline: scroll(root block);
+  }
+}