feat: bootstrap MediaStationGo (Go + React rewrite of MediaStation)

Adopt the cropflre/nowen-video tech stack and rebuild the project from
scratch:

  - Backend: Go 1.25 + Gin + GORM + SQLite (WAL) + JWT + WebSocket hub.
    Layered packages config / database / model / repository / service /
    middleware / handler. Default admin (admin/admin123) seeded on first
    run; /api routes for auth, libraries, media, stream and admin
    panels. WebSocket scan-progress events at /api/ws.
  - Frontend: React 18 + Vite 5 + Tailwind 3.4 + Zustand + axios +
    react-router 6 + lucide-react + framer-motion + hls.js. Pages for
    Login / Home / Library / Search / MediaDetail / Player / Admin
    (Library, Users, Settings tabs).
  - Distribution: multi-arch Dockerfile (frontend -> backend -> Alpine
    runtime), docker-compose.yml, GitHub Actions for CI and GHCR
    publish, Makefile, env-prefixed config (MEDIASTATION_*).
  - Docs: README, CONTRIBUTING, .env.example, config.example.yaml.

Backend builds, vets and tests pass. Frontend builds via tsc -b && vite
build (250 kB JS / 16 kB CSS, gzipped 84 / 4 kB).

web/src/main.tsx

@@ -0,0 +1,22 @@
+import React from 'react'
+import ReactDOM from 'react-dom/client'
+import { BrowserRouter } from 'react-router-dom'
+import { Toaster } from 'react-hot-toast'
+
+import App from './App'
+import './index.css'
+
+// Application root: BrowserRouter + global toast container.
+ReactDOM.createRoot(document.getElementById('root') as HTMLElement).render(
+  <React.StrictMode>
+    <BrowserRouter>
+      <App />
+      <Toaster
+        position="top-right"
+        toastOptions={{
+          className: '!bg-surface-800 !text-white !border !border-white/10',
+        }}
+      />
+    </BrowserRouter>
+  </React.StrictMode>,
+)