fix(emby): 电影条目不下发空的 SeasonId/SeriesId，修复小幻影视起播失败

小幻影视（RodelPlayer）2.2610 会把电影条目的 SeasonId 空串原样传进自己的
播放准备逻辑并抛 ArgumentException（Parameter 'seasonId'），客户端日志里
表现为 failedStage=PreparationFailed、playback generation null，也就是
点播放立刻「播放失败」；剧集条目的 SeasonId 非空，所以同一台设备放剧集正常。

Emby/Jellyfin 对「不适用」的字段是直接不下发（JSON 里没有该键）而不是下发空串。
这里对非剧集条目省略 SeasonId/SeriesId/SeasonName/SeriesName（顺带去掉电影被
标成「特别篇」的 SeasonName），剧集则保留真实季/剧信息、只清空值。

同时回退上一版针对 115 直链 UA 绑定的同源一跳改动：客户端日志显示该客户端的
播放器层与 API 层 UA 是一致的（剧集走服务端换链后的一跳直连可以正常解码播放），
不需要为此牺牲起播速度。

internal/handler/emby_playback.go

@@ -348,12 +348,6 @@ func embyVideoStreamHandler(svc *service.Container, cloudMode string) gin.Handle
 		// 此前这里把所有错误一律吞成 404：云盘 Cookie 过期、直链解析失败、
 		// STRM 播放被关闭……在第三方播放器上全部表现为「404 不存在」，
 		// 无法排查。现在区分：行不存在→404；云盘播放不可用/上游故障→502+原因。
-		//
-		// 网盘直链与换取时的 UA 严格绑定，而 Emby 客户端的 API 层与播放器层 UA
-		// 不保证相同（浏览器一定相同），所以只有浏览器客户端允许服务端短路换链。
-		if !isBrowserLikeUserAgent(c.GetHeader("User-Agent")) {
-			c.Request = c.Request.WithContext(service.WithClientSideSTRMResolve(c.Request.Context()))
-		}
 		err = svc.Stream.ServeFileWithCloudMode(c.Writer, c.Request, c.Param("id"), cloudMode)
 		switch {
 		case err == nil:
@@ -393,25 +387,6 @@ func embyPlaybackRedirectToken(c *gin.Context, svc *service.Container) string {
 	return token
 }
 
-// isBrowserLikeUserAgent 判断请求是否来自浏览器（含 WebView / Electron 客户端）。
-//
-// 只有浏览器能保证「API 请求」与「<video> 拉流」用同一个 User-Agent，因此也只有
-// 浏览器客户端可以安全地接受服务端换链后的 CDN 直链（见
-// service.WithClientSideSTRMResolve 说明）。原生播放器的播放器层与 API 层 UA
-// 不保证一致，必须让客户端自己去同源 strm 端点换链。
-func isBrowserLikeUserAgent(ua string) bool {
-	ua = strings.ToLower(strings.TrimSpace(ua))
-	if ua == "" {
-		return false
-	}
-	for _, marker := range []string{"mozilla/", "applewebkit/", "gecko/"} {
-		if strings.Contains(ua, marker) {
-			return true
-		}
-	}
-	return false
-}
-
 func embyShouldRedirectVideoStreamToSTRM(c *gin.Context, svc *service.Container, mediaID, cloudMode string) bool {
 	if c == nil || svc == nil || svc.Repo == nil || svc.Repo.Media == nil || cloudMode != service.CloudPlaybackModeRedirectProxy {
 		return false

internal/handler/emby_video_stream_resolve_test.go

@@ -1,138 +0,0 @@
-package handler
-
-import (
-	"context"
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-
-	"github.com/gin-gonic/gin"
-	"github.com/glebarez/sqlite"
-	"go.uber.org/zap"
-	"gorm.io/gorm"
-
-	"github.com/truewhile/MeBox/internal/config"
-	"github.com/truewhile/MeBox/internal/model"
-	"github.com/truewhile/MeBox/internal/repository"
-	"github.com/truewhile/MeBox/internal/service"
-	"github.com/truewhile/MeBox/internal/service/cloud"
-)
-
-// newEmbyStreamResolveTestContainer 造一个最小的 Emby 播放容器：一条云盘 strm 媒体
-// 加一个必定被调用的换链解析器，用于观察服务端是否替客户端换链。
-func newEmbyStreamResolveTestContainer(t *testing.T, resolver *countingStrmResolver) *service.Container {
-	t.Helper()
-	gin.SetMode(gin.TestMode)
-	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
-	if err != nil {
-		t.Fatalf("open db: %v", err)
-	}
-	if err := db.AutoMigrate(&model.Media{}, &model.Setting{}, &model.StrmAccount{}, &model.Library{}, &model.User{}); err != nil {
-		t.Fatalf("migrate: %v", err)
-	}
-	if err := db.Create(&model.Media{
-		Base:      model.Base{ID: "cloud-1"},
-		Title:     "Cloud",
-		Path:      "cloud://cloud115/Movie.mkv",
-		Container: "strm",
-		STRMURL:   "/api/strm/play/cloud115/video.mkv?acct=a1&pickcode=pc1",
-	}).Error; err != nil {
-		t.Fatalf("seed media: %v", err)
-	}
-	repos := repository.New(db)
-	cfg := &config.Config{}
-	log := zap.NewNop()
-	return &service.Container{
-		Cfg:    cfg,
-		Log:    log,
-		Repo:   repos,
-		Emby:   service.NewEmbyService(cfg, log, repos),
-		Stream: service.NewStreamService(cfg, log, repos, nil).SetStrmPlayTargetResolver(resolver.Resolve),
-	}
-}
-
-type countingStrmResolver struct {
-	calls int
-}
-
-func (r *countingStrmResolver) Resolve(context.Context, string, string) (*service.StrmPlayResult, error) {
-	r.calls++
-	link := "https://cdnfhnfile.115cdn.net/637b/Movie.mkv?t=1&k=sig"
-	return &service.StrmPlayResult{
-		RedirectURL: link,
-		Link:        &cloud.DirectLink{URL: link, Headers: map[string]string{"User-Agent": "ua"}},
-	}, nil
-}
-
-func serveEmbyVideoStream(t *testing.T, svc *service.Container, userAgent string) *httptest.ResponseRecorder {
-	t.Helper()
-	rec := httptest.NewRecorder()
-	c, _ := gin.CreateTestContext(rec)
-	c.Request = httptest.NewRequest(http.MethodGet, "/emby/Videos/cloud-1/stream?api_key=jwt123", nil)
-	c.Request.Header.Set("User-Agent", userAgent)
-	c.Params = gin.Params{{Key: "id", Value: "cloud-1"}}
-	embyVideoStreamHandler(svc, service.CloudPlaybackModeRedirectProxy)(c)
-	return rec
-}
-
-// 115 直链与换取时的 User-Agent 严格绑定（换错一个字符 CDN 就 403），而原生
-// 播放器（小幻影视 / RodelPlayer）的 API 层与播放器层 UA 并不一致，因此对非
-// 浏览器客户端绝不能在服务端替它换链，必须让客户端自己去同源端点换链。
-func TestEmbyVideoStreamDoesNotResolveDirectLinkForNativePlayer(t *testing.T) {
-	resolver := &countingStrmResolver{}
-	svc := newEmbyStreamResolveTestContainer(t, resolver)
-
-	w := serveEmbyVideoStream(t, svc, "RodelPlayer/2.2610.2.0 (Windows NT 10.0.26200; x64)")
-
-	if w.Code != http.StatusFound {
-		t.Fatalf("status = %d body=%s, want 302", w.Code, w.Body.String())
-	}
-	if resolver.calls != 0 {
-		t.Fatalf("server-side resolve called %d times, want 0", resolver.calls)
-	}
-	loc := w.Header().Get("Location")
-	if !strings.Contains(loc, "/api/strm/play/cloud115/video.mkv") {
-		t.Fatalf("Location = %q, want the same-origin strm endpoint", loc)
-	}
-	if strings.Contains(loc, "115cdn.net") {
-		t.Fatalf("Location = %q, must not point straight at the CDN for a native player", loc)
-	}
-}
-
-// 浏览器的 XHR 与 <video> 拉流必然是同一个 UA，可以继续享受服务端换链少一跳。
-func TestEmbyVideoStreamResolvesDirectLinkForBrowser(t *testing.T) {
-	resolver := &countingStrmResolver{}
-	svc := newEmbyStreamResolveTestContainer(t, resolver)
-
-	w := serveEmbyVideoStream(t, svc, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36")
-
-	if w.Code != http.StatusFound {
-		t.Fatalf("status = %d body=%s, want 302", w.Code, w.Body.String())
-	}
-	if resolver.calls != 1 {
-		t.Fatalf("server-side resolve called %d times, want 1", resolver.calls)
-	}
-	if loc := w.Header().Get("Location"); !strings.Contains(loc, "115cdn.net") {
-		t.Fatalf("Location = %q, want the resolved direct link", loc)
-	}
-}
-
-func TestIsBrowserLikeUserAgent(t *testing.T) {
-	cases := []struct {
-		ua   string
-		want bool
-	}{
-		{"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36", true},
-		{"Mozilla/5.0 (iPhone; CPU iPhone OS 18_0 like Mac OS X) AppleWebKit/605.1.15", true},
-		{"RodelPlayer/2.2610.2.0 (Windows NT 10.0.26200; x64)", false},
-		{"Yamby/2.0.5.5(Android", false},
-		{"Infuse-Direct/8.0", false},
-		{"", false},
-	}
-	for _, tc := range cases {
-		if got := isBrowserLikeUserAgent(tc.ua); got != tc.want {
-			t.Fatalf("isBrowserLikeUserAgent(%q) = %v, want %v", tc.ua, got, tc.want)
-		}
-	}
-}