feat: add auto-select from preferences and type picker

- Add MediaTypeAsk (0) as the default, mapping old video_audio to Ask
- Show Video/Audio/Ask type picker when no default media type is set
- Auto-select matching format and skip picker when defaults are configured
- Add autoSelectVideoFormat / autoSelectAudioFormat helpers with closest-match
- Add buildFilteredFormatList for type-filtered format lists
- Add Media Type setting in settings UI (Ask/Video/Audio)
- Add --merge-output-format mp4 for video downloads via yt-dlp
- Fix formatLabelForDisplay to show Height fallback and Extension
- Add cookies volume mount to docker-compose.yml
- Document cookies setup and new features in README

internal/handler/settings.go

@@ -25,11 +25,22 @@ func (h *Handler) buildSettingsKeyboard(userID int64, prefs *domain.UserPreferen
 		langLabel = "Default"
 	}
 
+	mediaTypeLabel := "Ask"
+	switch prefs.DefaultMediaType {
+	case domain.MediaTypeAudio:
+		mediaTypeLabel = "Audio"
+	case domain.MediaTypeVideo:
+		mediaTypeLabel = "Video"
+	}
+
 	rows := [][]models.InlineKeyboardButton{
 		{
-			{Text: fmt.Sprintf("Quality: %s/%s", audioFmt, videoFmt), CallbackData: "settings_quality"},
+			{Text: fmt.Sprintf("Media Type: %s", mediaTypeLabel), CallbackData: "settings_mediatype"},
 			{Text: fmt.Sprintf("Language: %s", langLabel), CallbackData: "settings_language"},
 		},
+		{
+			{Text: fmt.Sprintf("Quality: %s/%s", audioFmt, videoFmt), CallbackData: "settings_quality"},
+		},
 		{{Text: "Delete all data", CallbackData: "deleteaccount", Style: "danger"}},
 		{{Text: "Back to Menu", CallbackData: "back_menu"}},
 	}
@@ -62,6 +73,9 @@ func (h *Handler) handleSettingsSelection(ctx context.Context, chatID int64, msg
 	}
 
 	switch setting {
+	case "mediatype":
+		text, kb := h.buildMediaTypePicker(prefs)
+		h.editText(ctx, chatID, msgID, text, &kb)
 	case "quality":
 		text, kb := h.buildQualityAudioVideoPicker(prefs)
 		h.editText(ctx, chatID, msgID, text, &kb)
@@ -155,6 +169,31 @@ func (h *Handler) buildLanguagePicker(prefs *domain.UserPreferences) (string, mo
 	return "Select default language:", models.InlineKeyboardMarkup{InlineKeyboard: rows}
 }
 
+func (h *Handler) buildMediaTypePicker(prefs *domain.UserPreferences) (string, models.InlineKeyboardMarkup) {
+	options := []struct {
+		mt    domain.MediaType
+		label string
+	}{
+		{domain.MediaTypeAsk, "Ask"},
+		{domain.MediaTypeVideo, "Video"},
+		{domain.MediaTypeAudio, "Audio"},
+	}
+	rows := [][]models.InlineKeyboardButton{}
+	for _, opt := range options {
+		label := opt.label
+		if opt.mt == prefs.DefaultMediaType {
+			label = "> " + label
+		}
+		rows = append(rows, []models.InlineKeyboardButton{
+			{Text: label, CallbackData: "settings_set_mediatype_" + opt.mt.String()},
+		})
+	}
+	rows = append(rows, []models.InlineKeyboardButton{
+		{Text: "Back to Settings", CallbackData: "back_settings"},
+	})
+	return "Select default media type:", models.InlineKeyboardMarkup{InlineKeyboard: rows}
+}
+
 func (h *Handler) handleSettingsSet(ctx context.Context, chatID int64, msgID int, userID int64, setting string) {
 	parts := strings.SplitN(setting, "_", 2)
 	if len(parts) < 2 {
@@ -170,6 +209,16 @@ func (h *Handler) handleSettingsSet(ctx context.Context, chatID int64, msgID int
 
 	changed := false
 	switch action {
+	case "mediatype":
+		switch value {
+		case "ask":
+			prefs.DefaultMediaType = domain.MediaTypeAsk
+		case "audio":
+			prefs.DefaultMediaType = domain.MediaTypeAudio
+		case "video":
+			prefs.DefaultMediaType = domain.MediaTypeVideo
+		}
+		changed = true
 	case "audioquality":
 		prefs.DefaultAudioFormat = value
 		changed = true