feat: complete Vue UI parity (full backend + frontend)

== New domain models (7) ==
- UserPermission: per-user feature toggles (13 booleans)
- StorageConfig: encrypted Alist/S3/WebDAV adapters
- LicenseKey + LicenseActivation: offline license issuance
- DownloadClient: multi-client downloader configs
- AssistantSession + AssistantMessage: multi-turn AI chat persistence

== New services (5) ==
- PermissionService: admin grants always-true; user defaults seeded
- StorageConfigService: AES-GCM encryption + per-type connection probe
- LicenseService: 24-char hyphenated key generation, activation/heartbeat
- DownloadClientService: qB/Aria2/Transmission CRUD + WebUI test
- AssistantService: chat history + execute/undo stubs (op_id tracking)

== Extended AIService.Chat ==
- Multi-turn LLM call with chat history; offline fallback reply

== New endpoints (60+) ==
Auth:
  POST /auth/refresh, /auth/logout, /auth/change-password
  PATCH /auth/profile
  GET /auth/permissions, /auth/me

Permissions admin:
  GET/PUT /admin/users/:id/permissions
  POST /admin/users/:id/permissions/reset

Search:
  GET /search, /search/advanced, /search/tmdb, /search/sites

System:
  GET /system/config, /settings/schema, /system/events/ticket
  POST /admin/system/scheduler/:name/trigger

Stats:
  GET /stats/user/:id, /stats/top-users
  POST /stats/play

Sites:
  GET /sites/:id/resource, /sites/:id/userdata

Subscriptions:
  PUT /subscriptions/:id, POST /subscriptions/:id/search

Playlists:
  POST /playlists/:id/reorder
  DELETE /playlists/:id/items/by-id/:item_id

DLNA per-renderer:
  POST /dlna/:uuid/{play,pause,stop}, GET /dlna/:uuid/status

Media:
  POST/DELETE /media/:id/favorite, GET /media/:id/favorite/status
  POST /media/:id/ai-scrape, /media/scrape/test, /media/organize
  GET /favorites (alias)

Playback:
  GET /playback/:id/info, /playback/:id/external-players, /playback/:id/external-url
  POST /playback/:id/progress
  GET /playback/transcode/:job_id/status

Downloads:
  POST /download/:id/{pause,resume,organize}
  POST /download/{organize,sync,start-auto-sync}
  GET /download/tasks
  Admin: full CRUD on /admin/download/clients + /admin/download/aria2/stats

License:
  POST /license/{activate,heartbeat}
  GET /license/{status,heartbeat-status}
  Admin: /admin/license/{generate,list,:id/activations,:id/revoke,activation/:id/unbind}

Storage:
  GET /admin/storage/{status,:type}
  PUT /admin/storage/:type, POST /admin/storage/:type/test

Assistant (multi-turn AI):
  GET/POST /admin/assistant/sessions
  GET/DELETE /admin/assistant/session/:id
  POST /admin/assistant/{chat,execute}
  POST /admin/assistant/undo/:op_id
  GET /admin/assistant/history

== New React pages (4) ==
- AssistantChatPage (/assistant): full multi-turn chat UI with sessions
  sidebar, optimistic user-turn append, live AI response.
- DownloadClientsPage (/download-clients): typed CRUD form for
  qBittorrent / Aria2 / Transmission + per-row Test action.
- LicensePage (/license): generate keys, list activations, revoke,
  unbind individual devices.
- StorageConfigPage (/storage-config): tabbed Alist/WebDAV/S3 form
  with secret-aware redaction + connection probe.

== New API helpers (5) ==
- assistant, download_clients, license, permissions, storage_config

== Layout ==
- Sidebar gains 4 new admin links (AI 对话, 下载器, 外部存储, 许可证).

web/src/pages/StorageConfigPage.tsx

@@ -0,0 +1,187 @@
+import { FormEvent, useEffect, useMemo, useState } from 'react'
+import { Cloud, Loader2, Save, Send } from 'lucide-react'
+import toast from 'react-hot-toast'
+
+import { storageAPI, type StorageType } from '../api/storage_config'
+
+// StorageConfigPage manages the Alist / S3 / WebDAV adapters used by
+// the import / playback / STRM subsystems. Mirrors the Vue UI's
+// `admin/storage/*` tabs in a tabbed React surface.
+export function StorageConfigPage() {
+  const [active, setActive] = useState<StorageType>('alist')
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center gap-3">
+        <div className="flex h-10 w-10 items-center justify-center rounded-xl bg-blue-400/10 text-blue-300">
+          <Cloud size={20} />
+        </div>
+        <div>
+          <h1 className="font-display text-3xl font-bold text-white">外部存储</h1>
+          <p className="text-sm text-slate-400">
+            配置 Alist / S3 / WebDAV 后端,支持密码加密存储 + 在线测试
+          </p>
+        </div>
+      </div>
+
+      <div className="flex gap-2 border-b border-white/10">
+        {(['alist', 'webdav', 's3'] as StorageType[]).map((t) => (
+          <button
+            key={t}
+            onClick={() => setActive(t)}
+            className={
+              'border-b-2 px-4 py-2 text-sm uppercase ' +
+              (active === t
+                ? 'border-primary-400 text-primary-400'
+                : 'border-transparent text-slate-400 hover:text-white')
+            }
+          >
+            {t}
+          </button>
+        ))}
+      </div>
+
+      <StorageForm key={active} type={active} />
+    </div>
+  )
+}
+
+const FIELD_DEFS: Record<StorageType, { key: string; label: string; secret?: boolean; placeholder?: string }[]> = {
+  alist: [
+    { key: 'server', label: 'Server URL', placeholder: 'https://alist.example.com' },
+    { key: 'token', label: 'Token', secret: true },
+  ],
+  webdav: [
+    { key: 'url', label: 'URL', placeholder: 'https://example.com/dav/' },
+    { key: 'username', label: '用户名' },
+    { key: 'password', label: '密码', secret: true },
+  ],
+  s3: [
+    { key: 'endpoint', label: 'Endpoint', placeholder: 'https://s3.amazonaws.com' },
+    { key: 'region', label: 'Region', placeholder: 'us-east-1' },
+    { key: 'bucket', label: 'Bucket' },
+    { key: 'access_key', label: 'Access Key', secret: true },
+    { key: 'secret_key', label: 'Secret Key', secret: true },
+    { key: 'force_path_style', label: 'force_path_style (true/false)' },
+  ],
+}
+
+function StorageForm({ type }: { type: StorageType }) {
+  const fields = useMemo(() => FIELD_DEFS[type], [type])
+  const [config, setConfig] = useState<Record<string, string>>({})
+  const [enabled, setEnabled] = useState(true)
+  const [loading, setLoading] = useState(true)
+  const [saving, setSaving] = useState(false)
+  const [testing, setTesting] = useState(false)
+
+  const refresh = async () => {
+    setLoading(true)
+    try {
+      const r = await storageAPI.get(type)
+      const next: Record<string, string> = {}
+      for (const f of fields) {
+        const v = r.config?.[f.key]
+        // List() redacts secrets to "********"; show empty so the user
+        // doesn't accidentally save the placeholder.
+        next[f.key] = v === '********' ? '' : v ?? ''
+      }
+      setConfig(next)
+      setEnabled(r.enabled)
+    } catch {
+      const next: Record<string, string> = {}
+      for (const f of fields) next[f.key] = ''
+      setConfig(next)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  useEffect(() => {
+    refresh().catch(() => undefined)
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [type])
+
+  const onSave = async (e: FormEvent) => {
+    e.preventDefault()
+    setSaving(true)
+    try {
+      await storageAPI.save(type, config, enabled)
+      toast.success('已保存')
+      await refresh()
+    } catch (err: unknown) {
+      const msg =
+        (err as { response?: { data?: { error?: string } } })?.response?.data?.error ??
+        '保存失败'
+      toast.error(msg)
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  const onTest = async () => {
+    setTesting(true)
+    try {
+      const r = await storageAPI.test(type, config)
+      if (r.ok) toast.success('连接成功')
+      else toast.error(r.error ?? '连接失败')
+    } catch (err: unknown) {
+      const msg =
+        (err as { response?: { data?: { error?: string } } })?.response?.data?.error ??
+        '测试失败'
+      toast.error(msg)
+    } finally {
+      setTesting(false)
+    }
+  }
+
+  if (loading) {
+    return (
+      <div className="flex justify-center py-12 text-slate-400">
+        <Loader2 className="animate-spin" />
+      </div>
+    )
+  }
+
+  return (
+    <form onSubmit={onSave} className="glass-panel space-y-4">
+      {fields.map((f) => (
+        <label key={f.key} className="block">
+          <span className="mb-1 block text-sm text-slate-300">
+            {f.label}
+            <span className="ml-2 font-mono text-[10px] text-slate-600">{f.key}</span>
+          </span>
+          <input
+            type={f.secret ? 'password' : 'text'}
+            className="input-base"
+            placeholder={f.placeholder}
+            value={config[f.key] ?? ''}
+            onChange={(e) => setConfig((c) => ({ ...c, [f.key]: e.target.value }))}
+          />
+        </label>
+      ))}
+      <label className="flex items-center gap-2 text-sm text-slate-300">
+        <input
+          type="checkbox"
+          className="h-4 w-4 accent-primary-400"
+          checked={enabled}
+          onChange={(e) => setEnabled(e.target.checked)}
+        />
+        启用
+      </label>
+      <div className="flex justify-end gap-2 pt-2">
+        <button
+          type="button"
+          onClick={onTest}
+          disabled={testing}
+          className="rounded border border-white/10 px-4 py-2 text-sm text-slate-300 hover:bg-white/5"
+        >
+          {testing ? <Loader2 size={14} className="inline animate-spin" /> : <Send size={14} className="inline" />}
+          {' '}测试
+        </button>
+        <button type="submit" disabled={saving} className="neon-button">
+          {saving ? <Loader2 size={16} className="animate-spin" /> : <Save size={16} />}
+          保存
+        </button>
+      </div>
+    </form>
+  )
+}