feat(api): streaming, transcoding, events, history and likes (M3)

- tracks carry a stream_url signed for the user for 12 h and the
  user's reaction; /stream checks the signature, expiry and that the
  user is not blocked, then hands the file to nginx by X-Accel-Redirect
  (or serves it with Range support when X_ACCEL=false)
- original by default; formats browsers can't play and explicit
  high/medium/low go through Opus transcoding, never upwards: a lossy
  source under the target bitrate stays original; transcodes are
  cached per file and size, deduplicated in flight, limited by
  TRANSCODE_CONCURRENCY and trimmed hourly by LRU to the size limit
- /events takes up to 500 events with client UUIDs, drops repeats and
  events older than 30 days, counts plays (≥ half or 4 min, or
  finished), early skips and history entries (≥ 30 s)
- history with clearing, likes and dislikes with cursors and totals,
  track reactions, playback state with last-write-wins, tracks batch

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/api/internal/server/router.go

@@ -12,6 +12,7 @@ import (
 	"pipu/api/internal/auth"
 	"pipu/api/internal/library"
 	"pipu/api/internal/platform/httpx"
+	"pipu/api/internal/playback"
 	"pipu/api/internal/search"
 	"pipu/api/internal/system"
 )
@@ -24,6 +25,8 @@ type Deps struct {
 	// Library — хранилища, сканы и каталог.
 	Library *library.Handler
 	Search  *search.Handler
+	// Playback — стрим, события, история, реакции, состояние плеера.
+	Playback *playback.Handler
 	// AuthService проверяет access-токены в middleware. nil — только для тестов служебных эндпоинтов.
 	AuthService *auth.Service
 }
@@ -32,10 +35,11 @@ type Deps struct {
 // По мере появления модулей (catalog, ...) они встраиваются сюда.
 // Алиасы дают встроенным полям разные имена: у модулей одинаковое имя типа Handler.
 type (
-	systemHandler  = system.Handler
-	authHandler    = auth.Handler
-	libraryHandler = library.Handler
-	searchHandler  = search.Handler
+	systemHandler   = system.Handler
+	authHandler     = auth.Handler
+	libraryHandler  = library.Handler
+	searchHandler   = search.Handler
+	playbackHandler = playback.Handler
 )
 
 type handlers struct {
@@ -43,6 +47,7 @@ type handlers struct {
 	*authHandler
 	*libraryHandler
 	*searchHandler
+	*playbackHandler
 }
 
 var _ gen.StrictServerInterface = handlers{}
@@ -62,10 +67,11 @@ func NewRouter(d Deps) http.Handler {
 	r.NotFound(httpx.NotFound)
 	r.MethodNotAllowed(httpx.MethodNotAllowed)
 
-	strict := gen.NewStrictHandlerWithOptions(handlers{systemHandler: d.System, authHandler: d.Auth, libraryHandler: d.Library, searchHandler: d.Search}, nil, gen.StrictHTTPServerOptions{
-		RequestErrorHandlerFunc:  httpx.RequestError,
-		ResponseErrorHandlerFunc: httpx.ResponseError(log),
-	})
+	strict := gen.NewStrictHandlerWithOptions(handlers{systemHandler: d.System, authHandler: d.Auth, libraryHandler: d.Library, searchHandler: d.Search, playbackHandler: d.Playback},
+		[]gen.StrictMiddlewareFunc{httpx.StrictRequest}, gen.StrictHTTPServerOptions{
+			RequestErrorHandlerFunc:  httpx.RequestError,
+			ResponseErrorHandlerFunc: httpx.ResponseError(log),
+		})
 	return gen.HandlerWithOptions(strict, gen.ChiServerOptions{
 		BaseRouter: r,
 		// Ошибки разбора path- и query-параметров — тоже problem+json, а не текст по умолчанию.