Initial commit: full-stack Bun + Elysia + React template

Elysia.js API with session-based auth (email/password + Google OAuth),
role system (USER/ADMIN/SUPER_ADMIN), Prisma + PostgreSQL, React 19
with Mantine UI, TanStack Router, dark theme, and comprehensive test
suite (unit, integration, E2E with Lightpanda).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/frontend/routes/__root.tsx

@@ -0,0 +1,14 @@
+import { Outlet, createRootRouteWithContext } from '@tanstack/react-router'
+import type { QueryClient } from '@tanstack/react-query'
+import { NotFound } from '@/frontend/components/NotFound'
+import { ErrorPage } from '@/frontend/components/ErrorPage'
+
+interface RouterContext {
+  queryClient: QueryClient
+}
+
+export const Route = createRootRouteWithContext<RouterContext>()({
+  component: () => <Outlet />,
+  notFoundComponent: NotFound,
+  errorComponent: ({ error }) => <ErrorPage error={error} />,
+})