Refactor layout and home page for improved localization and session handling

- Updated RootLayout to include locale support and integrated ThemeProvider and LocaleProvider for better internationalization.
- Replaced static home page content with a redirect based on user session status, enhancing user experience by directing to the appropriate dashboard or login page.
- Switched font from Geist to Inter for improved typography consistency.

apps/webui/src/middleware.ts

@@ -0,0 +1,28 @@
+import { NextResponse, type NextRequest } from 'next/server';
+
+// Kept as a literal (not imported from `lib/session.ts`) on purpose: the
+// Edge middleware runtime cannot bundle the Redis/Node-only code that
+// `lib/session.ts` pulls in, so this file must stay dependency-free.
+const SESSION_COOKIE_NAME = 'nexumi_session';
+
+/**
+ * Lightweight edge-safe guard: only checks that the session cookie exists.
+ * The actual session and permission validation happens in
+ * `requireAuthOrRedirect` / `requireGuildAccessOrRedirect` inside the
+ * dashboard layouts, since that requires Redis/Prisma access which is not
+ * available in the middleware runtime.
+ */
+export function middleware(request: NextRequest) {
+  const hasSession = request.cookies.has(SESSION_COOKIE_NAME);
+
+  if (!hasSession) {
+    const loginUrl = new URL('/login', request.url);
+    return NextResponse.redirect(loginUrl);
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: ['/dashboard/:path*']
+};