feat(audiobooks): list endpoint at GET /api/v1/audiobooks

Paginated list of media_items with type='audiobook' scoped to the
caller's accessible libraries via the existing access filter.
Mirrors silo's existing list-style handlers for movies and series.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/api/handlers/audiobooks_list.go

@@ -0,0 +1,70 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+
+	"github.com/Silo-Server/silo-server/internal/catalog"
+	"github.com/Silo-Server/silo-server/internal/models"
+)
+
+// AudiobookHandler serves silo-native audiobook endpoints under
+// /api/v1/audiobooks/*. Sub-plan 3 implements list/detail/progress;
+// sub-plan 4's ABS-compat layer is separate.
+type AudiobookHandler struct {
+	Items *catalog.ItemRepository
+}
+
+// HandleListAudiobooks serves GET /api/v1/audiobooks?limit=&offset=.
+// Paginated catalog of media_items with type='audiobook' scoped to the
+// caller's accessible libraries.
+func (h *AudiobookHandler) HandleListAudiobooks(w http.ResponseWriter, r *http.Request) {
+	limit, _ := strconv.Atoi(r.URL.Query().Get("limit"))
+	if limit <= 0 || limit > 200 {
+		limit = 50
+	}
+	offset, _ := strconv.Atoi(r.URL.Query().Get("offset"))
+	if offset < 0 {
+		offset = 0
+	}
+	filter := requestAccessFilter(r)
+	items, total, err := h.Items.Search(r.Context(), "", []string{"audiobook"}, limit, offset, filter)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "internal_error", "list audiobooks failed")
+		return
+	}
+	resp := struct {
+		Items  []audiobookListItem `json:"items"`
+		Total  int                 `json:"total"`
+		Limit  int                 `json:"limit"`
+		Offset int                 `json:"offset"`
+	}{
+		Items:  audiobookListItems(items),
+		Total:  total,
+		Limit:  limit,
+		Offset: offset,
+	}
+	w.Header().Set("Content-Type", "application/json")
+	_ = json.NewEncoder(w).Encode(resp)
+}
+
+type audiobookListItem struct {
+	ContentID string `json:"content_id"`
+	Title     string `json:"title"`
+	Year      int    `json:"year"`
+	PosterURL string `json:"poster_url,omitempty"`
+}
+
+func audiobookListItems(items []*models.MediaItem) []audiobookListItem {
+	out := make([]audiobookListItem, 0, len(items))
+	for _, it := range items {
+		out = append(out, audiobookListItem{
+			ContentID: it.ContentID,
+			Title:     it.Title,
+			Year:      it.Year,
+			PosterURL: it.PosterPath,
+		})
+	}
+	return out
+}

internal/api/router.go

@@ -1554,6 +1554,12 @@ func NewRouter(deps Dependencies) chi.Router {
 				r.Get("/sections/recipes", recipeHandler.HandleList)
 				r.Get("/sections/recipes/{type}/candidates", recipeHandler.HandleCandidates)
 
+				// Audiobook endpoints (no profile required — catalog-level list).
+				if itemRepo != nil {
+					audiobookHandler := &handlers.AudiobookHandler{Items: itemRepo}
+					r.Get("/audiobooks", audiobookHandler.HandleListAudiobooks)
+				}
+
 				// Section endpoints (profile-scoped).
 				if sectionHandler != nil {
 					r.Group(func(r chi.Router) {