feat: port missing MediaStation features (DLNA, STRM, files, dup, sched, api-configs, emby, storage)

Audit-driven port from the original Python MediaStation. Eight major
subsystems that were absent from the Go rewrite are now in place,
each with its own service, handler, frontend page and smoke-test
assertions.

Backend services
  - service/crypto.go: AES-256-GCM encrypt/decrypt for at-rest secrets
    keyed off the JWT secret. Legacy plaintext rows pass through
    unchanged for smooth upgrades. Unit-tested.
  - service/api_config.go: third-party provider config (TMDb, Bangumi,
    TheTVDB, Fanart, Douban, OpenAI). Seeds defaults on first run.
    Encrypts api_key on write, returns masked 'abc1****wxyz' projection.
  - service/duplicate.go: sparse-sample MD5 (head + middle + tail, 1MiB
    each, plus file-size suffix) duplicate finder. Picks 'best' primary
    (matched > size > id) and marks others is_duplicate=true.
  - service/filemanager.go: server-side allow-listed file browser used
    by the library-path picker. Strict path-traversal protection.
  - service/dlna.go: real SSDP M-SEARCH discovery + AVTransport
    SetAVTransportURI/Play SOAP cast. 30 s discovery cache.
  - service/scheduler.go: 3 recurring background jobs (library_scan
    60min, transcode_cleanup 24h, recycle_purge 24h with 30-day
    cutoff). Status + run-now endpoints.
  - service/cache_cleanup.go: walkAndPrune helper used by scheduler.
  - service/storage.go: DB-only disk-usage breakdown by library and by
    container format.
  - service/emby_compat.go: read-only Emby/Jellyfin shim
    (System/Info, Users, Users/x/Views, Items, PlaybackInfo) so Infuse
    / VidHub / Kodi can browse MediaStationGo libraries.

Model updates
  - Media: new strm_url (302 redirect target), file_hash, is_duplicate,
    duplicate_of fields.
  - APIConfig: new table for encrypted provider secrets.
  - AutoMigrate registers APIConfig.

Stream layer
  - StreamService.ServeFile now redirects 302 to strm_url when set so
    WebDAV / Alist / S3 / HTTP direct links work transparently.

Handlers + routes
  - Authed: GET /files, GET /storage, GET /dlna/devices, POST /dlna/cast,
    PUT/DELETE /media/:id/strm, POST /strm/import,
    POST /duplicates/{scan,unmark}.
  - Admin: GET/PUT/DELETE /admin/api-configs/:provider,
    GET /admin/scheduler, POST /admin/scheduler/:name/run.
  - New /emby/* group: System/Info, Users, Users/:userId/Views,
    Users/:userId/Items, Items/:id/PlaybackInfo (auth-required).

Frontend pages (lazy-loaded, 7 new chunks)
  - DlnaPage: device list + media picker + cast button.
  - FileManagerPage: root selector + breadcrumb + sortable listing.
  - APIConfigsPage: per-provider card with masked-key editor.
  - StoragePage: usage tiles + per-library bars + per-container grid.
  - DuplicatesPage: scan form + grouped report with primary highlight.
  - SchedulerPage: live job table with run-now button (5s refresh).
  - Sidebar reorganised: 自动化 group adds DLNA, 管理 group adds
    存储 / 文件浏览 / 重复文件 / 定时任务 / API 配置.

Smoke test additions (all admin-only)
  - api-configs seeded with 6 providers
  - api-config encrypted in db (sqlite3 enc:v1: prefix check)
  - storage breakdown
  - file browser lists library root + rejects /etc (path traversal)
  - dlna devices endpoint
  - scheduler exposes 3 jobs + run library_scan
  - emby /System/Info + /Users/{x}/Views
  - strm set + stream 302 + strm clear
  - duplicate scan

Verified: go build, go vet, go test (incl. new TestCrypto* suite + the
existing TestParseEpisode/TestCleanQuery/TestSrtToVTT/TestStripASSTags/
TestBuildFFmpegArgs); tsc -b && vite build emits 28 route chunks plus
the deferred hls chunk; main bundle 253 KB / 85 KB gzipped; smoke test
PASS=42 / FAIL=0.

web/src/api/api_configs.ts

@@ -0,0 +1,30 @@
+import { api } from './client'
+
+export interface APIConfig {
+  id: string
+  provider: string
+  base_url?: string
+  extra?: string
+  enabled: boolean
+  description?: string
+  has_key: boolean
+  masked_key?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface APIConfigPatch {
+  api_key?: string
+  base_url?: string
+  extra?: string
+  enabled?: boolean
+  description?: string
+}
+
+export const apiConfigsAPI = {
+  list: () => api.get<{ items: APIConfig[] }>('/admin/api-configs').then((r) => r.data.items),
+  get: (provider: string) => api.get<APIConfig>(`/admin/api-configs/${provider}`).then((r) => r.data),
+  update: (provider: string, patch: APIConfigPatch) =>
+    api.put<APIConfig>(`/admin/api-configs/${provider}`, patch).then((r) => r.data),
+  remove: (provider: string) => api.delete(`/admin/api-configs/${provider}`).then((r) => r.data),
+}

web/src/api/dlna.ts

@@ -0,0 +1,23 @@
+import { api } from './client'
+
+export interface DLNADevice {
+  udn: string
+  friendly_name: string
+  manufacturer: string
+  model_name: string
+  location: string
+  control_url: string
+  ip_address: string
+}
+
+export const dlnaAPI = {
+  list: (force = false) =>
+    api
+      .get<{ devices: DLNADevice[] }>('/dlna/devices', { params: { force: force ? 'true' : '' } })
+      .then((r) => r.data.devices),
+
+  cast: (controlURL: string, mediaURL: string) =>
+    api
+      .post('/dlna/cast', { control_url: controlURL, media_url: mediaURL })
+      .then((r) => r.data),
+}

web/src/api/duplicates.ts

@@ -0,0 +1,30 @@
+import { api } from './client'
+import type { Media } from '../types'
+
+export interface DuplicateGroup {
+  hash: string
+  primary: Media
+  duplicates: Media[]
+}
+
+export interface DuplicateReport {
+  total_scanned: number
+  groups_found: number
+  items_marked: number
+  groups: DuplicateGroup[]
+}
+
+export const duplicatesAPI = {
+  scan: (libraryID = '') =>
+    api
+      .post<DuplicateReport>('/duplicates/scan', null, {
+        params: libraryID ? { library_id: libraryID } : undefined,
+      })
+      .then((r) => r.data),
+  unmark: (libraryID = '') =>
+    api
+      .post<{ unmarked: number }>('/duplicates/unmark', null, {
+        params: libraryID ? { library_id: libraryID } : undefined,
+      })
+      .then((r) => r.data),
+}

web/src/api/files.ts

@@ -0,0 +1,23 @@
+import { api } from './client'
+
+export interface FileEntry {
+  name: string
+  path: string
+  is_dir: boolean
+  size: number
+  modified: number
+}
+
+export interface FileListing {
+  path: string
+  parent?: string
+  roots?: { label: string; path: string }[]
+  entries: FileEntry[] | null
+}
+
+export const filesAPI = {
+  list: (path = '', max = 1000) =>
+    api
+      .get<FileListing>('/files', { params: { path, max } })
+      .then((r) => r.data),
+}

web/src/api/scheduler.ts

@@ -0,0 +1,13 @@
+import { api } from './client'
+
+export interface JobStatus {
+  name: string
+  interval: string
+  last_run?: string
+  last_err?: string
+}
+
+export const schedulerAPI = {
+  status: () => api.get<{ jobs: JobStatus[] }>('/admin/scheduler').then((r) => r.data.jobs),
+  run: (name: string) => api.post(`/admin/scheduler/${name}/run`).then((r) => r.data),
+}

web/src/api/storage.ts

@@ -0,0 +1,28 @@
+import { api } from './client'
+
+export interface LibraryUsage {
+  library_id: string
+  name: string
+  type: string
+  path: string
+  media_count: number
+  total_bytes: number
+  total_seconds: number
+}
+
+export interface ContainerStat {
+  container: string
+  count: number
+  bytes: number
+}
+
+export interface StorageBreakdown {
+  total_bytes: number
+  total_seconds: number
+  by_library: LibraryUsage[]
+  by_container: ContainerStat[]
+}
+
+export const storageAPI = {
+  breakdown: () => api.get<StorageBreakdown>('/storage').then((r) => r.data),
+}

web/src/api/strm.ts

@@ -0,0 +1,9 @@
+import { api } from './client'
+
+export const strmAPI = {
+  set: (mediaID: string, url: string) =>
+    api.put(`/media/${mediaID}/strm`, { url }).then((r) => r.data),
+  clear: (mediaID: string) => api.delete(`/media/${mediaID}/strm`).then((r) => r.data),
+  importURL: (libraryID: string, title: string, url: string) =>
+    api.post('/strm/import', { library_id: libraryID, title, url }).then((r) => r.data),
+}