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/api/admin.ts

@@ -0,0 +1,15 @@
+import { api } from './client'
+import type { AccessLog, Setting, User } from '../types'
+
+export const adminAPI = {
+  listUsers: () => api.get<User[]>('/admin/users').then((r) => r.data),
+
+  deleteUser: (id: string) => api.delete(`/admin/users/${id}`).then((r) => r.data),
+
+  listSettings: () => api.get<Setting[]>('/admin/settings').then((r) => r.data),
+
+  updateSetting: (key: string, value: string) =>
+    api.put('/admin/settings', { key, value }).then((r) => r.data),
+
+  recentLogs: () => api.get<AccessLog[]>('/admin/logs').then((r) => r.data),
+}