feat(web): scaffold client-side rendered SPA foundation

- feat: initialize Vite project with React 19, React Router 8, TanStack
  Query, Ant Design 6, and Tailwind CSS 4
- feat: add Oxlint with React/TypeScript rules, strict TypeScript
  config, and layered CSS import order
- docs: add decision record for client-rendered Web foundation with
  React, Ant Design, and Tailwind CSS
- docs: create web roadmap defining architecture boundaries and deferred
  dependencies
- build: pin Node.js 24 in mise.toml

web/src/App.tsx

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+import { RouterProvider } from 'react-router'
+
+import { router } from './app/router.tsx'
+
+function App() {
+  return <RouterProvider router={router} />
+}
+
+export default App

web/src/app/providers.tsx

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+import type { PropsWithChildren } from 'react'
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { App as AntDesignApp, ConfigProvider } from 'antd'
+
+const queryClient = new QueryClient()
+
+export function AppProviders({ children }: PropsWithChildren) {
+  return (
+    <QueryClientProvider client={queryClient}>
+      <ConfigProvider>
+        <AntDesignApp>{children}</AntDesignApp>
+      </ConfigProvider>
+    </QueryClientProvider>
+  )
+}

web/src/app/router.tsx

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+import { createBrowserRouter } from 'react-router'
+
+import { HomePage } from '../pages/HomePage.tsx'
+import { NotFoundPage } from '../pages/NotFoundPage.tsx'
+
+export const router = createBrowserRouter([
+  {
+    path: '/',
+    element: <HomePage />,
+  },
+  {
+    path: '*',
+    element: <NotFoundPage />,
+  },
+])

web/src/index.css

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+@layer theme, base, antd, components, utilities;
+@import 'tailwindcss';
+
+html,
+body,
+#root {
+  min-width: 320px;
+  min-height: 100%;
+}
+
+body {
+  margin: 0;
+}

web/src/main.tsx

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+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import './index.css'
+import App from './App.tsx'
+import { AppProviders } from './app/providers.tsx'
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <AppProviders>
+      <App />
+    </AppProviders>
+  </StrictMode>,
+)

web/src/pages/HomePage.tsx

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+import { Card, Space, Tag, Typography } from 'antd'
+
+const { Paragraph, Title } = Typography
+
+export function HomePage() {
+  return (
+    <main className="grid min-h-screen place-items-center bg-slate-50 p-6">
+      <Card className="w-full max-w-xl">
+        <Space orientation="vertical" size="middle">
+          <Tag color="blue">MyGO Web</Tag>
+          <Title level={1}>MyGO</Title>
+          <Paragraph>
+            The client-side web application foundation is ready.
+          </Paragraph>
+        </Space>
+      </Card>
+    </main>
+  )
+}

web/src/pages/NotFoundPage.tsx

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+import { Button, Result } from 'antd'
+import { Link } from 'react-router'
+
+export function NotFoundPage() {
+  return (
+    <Result
+      status="404"
+      title="Page not found"
+      extra={
+        <Button type="primary">
+          <Link to="/">Back home</Link>
+        </Button>
+      }
+    />
+  )
+}