Add per-disk profiles with video transcoding support

Each disk stores .jukebox/profile.json with copy parameters (dest
folder, overwrite mode, file select, reserve space, auto-copy) and
optional transcoding limits for the target player (codec, resolution,
bitrate, FPS, audio channels, output format).

On copy, video files are probed with ffprobe; if they exceed the
profile limits they are transcoded via ffmpeg (-threads 0 for full
CPU usage), otherwise copied as-is. Scale filter never upscales.

New: internal/disk/profile.go, internal/transcoder/{detect,transcoder}.go
API: GET/PUT /api/disks/profile?mount_path=
UI: disk profile panel in dashboard for known disks
Dockerfile: adds ffmpeg to the runtime image

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/copier/copier.go

@@ -19,6 +19,7 @@ import (
 	"jukebox_maker/internal/db"
 	"jukebox_maker/internal/disk"
 	"jukebox_maker/internal/task"
+	"jukebox_maker/internal/transcoder"
 )
 
 type Options struct {
@@ -31,6 +32,7 @@ type Options struct {
 	ReserveFreeGB     float64
 	OverwriteMode     config.OverwriteMode
 	FileSelectMode    config.FileSelectMode
+	Transcode         *disk.TranscodeProfile // nil = не транскодировать
 }
 
 type Copier struct {
@@ -324,8 +326,14 @@ func (c *Copier) run(ctx context.Context, taskID string, opts Options, database
 		}
 
 		dstAbs := filepath.Join(destRoot, f.relPath)
-		if err := copyFile(ctx, f.srcAbs, dstAbs); err != nil {
-			if errors.Is(err, context.Canceled) {
+		var fileErr error
+		if opts.Transcode != nil && isVideoFile(f.srcAbs) {
+			fileErr = c.processVideo(ctx, taskID, database, opts.Transcode, f.srcAbs, dstAbs)
+		} else {
+			fileErr = copyFile(ctx, f.srcAbs, dstAbs)
+		}
+		if fileErr != nil {
+			if errors.Is(fileErr, context.Canceled) {
 				c.tasks.Update(taskID, func(t *task.Task) {
 					t.Status = task.StatusCanceled
 					t.Message = "Canceled"
@@ -353,6 +361,59 @@ func (c *Copier) run(ctx context.Context, taskID string, opts Options, database
 	setStatus(task.StatusSuccess, fmt.Sprintf("Done. Copied %d files.", copied), 100)
 }
 
+// videoExtensions — расширения видеофайлов из встроенного справочника.
+var videoExtensions = func() map[string]struct{} {
+	exts := config.BuiltInMediaTypeExtensions()[config.MediaTypeVideo]
+	set := make(map[string]struct{}, len(exts))
+	for _, e := range exts {
+		set[e] = struct{}{}
+	}
+	return set
+}()
+
+func isVideoFile(path string) bool {
+	_, ok := videoExtensions[strings.ToLower(filepath.Ext(path))]
+	return ok
+}
+
+// processVideo определяет: транскодировать или скопировать файл.
+func (c *Copier) processVideo(ctx context.Context, taskID string, database *db.DB, profile *disk.TranscodeProfile, src, dst string) error {
+	info, err := transcoder.ProbeVideo(src)
+	if err != nil {
+		// Не смогли зондировать — просто копируем
+		return copyFile(ctx, src, dst)
+	}
+
+	if !transcoder.NeedsTranscode(info, profile) {
+		return copyFile(ctx, src, dst)
+	}
+
+	// Меняем расширение выходного файла под формат контейнера
+	ext := transcoder.OutputExt(profile.OutputFormat)
+	dstTranscoded := strings.TrimSuffix(dst, filepath.Ext(dst)) + ext
+
+	c.tasks.Update(taskID, func(t *task.Task) {
+		t.Phase = task.PhaseTranscoding
+		t.Message = "Transcoding " + filepath.Base(src)
+	})
+	if t, ok := c.tasks.Get(taskID); ok {
+		_ = database.UpdateTask(*t)
+	}
+
+	progressFn := func(pct float64) {
+		c.tasks.Update(taskID, func(t *task.Task) {
+			t.Progress = int(pct * 100)
+		})
+	}
+
+	return transcoder.Transcode(ctx, transcoder.Options{
+		Input:      src,
+		Output:     dstTranscoded,
+		Profile:    profile,
+		SourceInfo: info,
+	}, progressFn)
+}
+
 type fileEntry struct {
 	srcAbs  string
 	relPath string // relative to /media