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/types/index.ts

@@ -0,0 +1,74 @@
+// Domain types mirrored from the Go backend (internal/model).
+
+export interface User {
+  id: string
+  username: string
+  role: 'admin' | 'user'
+  email?: string
+  avatar_url?: string
+  force_password_reset: boolean
+  last_login_at?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface Library {
+  id: string
+  name: string
+  path: string
+  type: string
+  enabled: boolean
+  created_at: string
+  updated_at: string
+}
+
+export interface Media {
+  id: string
+  library_id: string
+  series_id?: string
+  title: string
+  original_name?: string
+  path: string
+  size_bytes: number
+  duration_sec: number
+  width: number
+  height: number
+  video_codec?: string
+  audio_codec?: string
+  container?: string
+  poster_url?: string
+  backdrop_url?: string
+  overview?: string
+  rating: number
+  year: number
+  season_num: number
+  episode_num: number
+  scrape_status: string
+  tmdb_id: number
+  bangumi_id: number
+  nsfw: boolean
+  created_at: string
+  updated_at: string
+}
+
+export interface ScanResult {
+  library_id: string
+  visited: number
+  added: number
+}
+
+export interface Setting {
+  key: string
+  value: string
+  updated_at: string
+}
+
+export interface AccessLog {
+  id: string
+  user_id: string
+  action: string
+  target: string
+  ip: string
+  detail: string
+  created_at: string
+}