Final cleanup: Update remaining comments and variable names

Changes:
- Update comments: "Bookmann UUID" → "Bookhoard UUID"
- Rename sidecar struct field: Bookmann → Bookhoard
- Update type names: SidecarBookmannConfig → SidecarBookhoardConfig
- Fix test database name in queue_test.go
- Fix uppercase env var examples in KOBO_SETUP.md

Internal Go variable names (BookmannUuid, bookmannUUID) left unchanged
as they're implementation details that don't affect functionality.

Part of project rename to Bookhoard.

internal/handlers/kobo.go

@@ -25,13 +25,13 @@ func NewKoboHandler(db *database.Queries, connManager *wsync.ConnectionManager)
 	return &KoboHandler{db: db, connManager: connManager}
 }
 
-// mapContentIdToBookhoardUUID maps Kobo ContentId to Bookmann UUID with multiple fallback strategies
+// mapContentIdToBookhoardUUID maps Kobo ContentId to Bookhoard UUID with multiple fallback strategies
 // Phase 6: Enhanced Kobo Sync - ContentId Mapping Logic
 func (h *KoboHandler) mapContentIdToBookhoardUUID(ctx echo.Context, contentId string, deviceID uuid.UUID) (uuid.UUID, error, string) {
 	// Step 1: Try direct ContentId lookup in device_catalogs table
 	catalog, err := h.db.GetDeviceCatalogByKoboContentId(ctx.Request().Context(), contentId)
 	if err == nil && catalog.ID.Valid {
-		// Found! Use canonical Bookmann UUID
+		// Found! Use canonical Bookhoard UUID
 		return uuid.UUID(catalog.BookmannUuid.Bytes), nil, "catalog_match"
 	}
 
@@ -79,7 +79,7 @@ func (h *KoboHandler) mapContentIdToBookhoardUUID(ctx echo.Context, contentId st
 	return uuid.Nil, fmt.Errorf("unlinked book: ContentId %s not found", contentId), "unlinked"
 }
 
-// mapBookhoardUUIDToKoboContentId maps Bookmann UUID to Kobo ContentId
+// mapBookhoardUUIDToKoboContentId maps Bookhoard UUID to Kobo ContentId
 // Creates new entry in device_catalogs if not exists
 func (h *KoboHandler) mapBookhoardUUIDToKoboContentId(c echo.Context, bookmannUUID uuid.UUID, deviceID uuid.UUID) (string, error) {
 	// Check if catalog entry already exists

internal/handlers/sidecar.go

@@ -22,7 +22,7 @@ func NewSidecarHandler(db *database.Queries) *SidecarHandler {
 
 type SidecarConfig struct {
 	Version        string                 `json:"version"`
-	Bookmann       SidecarBookmannConfig  `json:"bookhoard"`
+	Bookhoard      SidecarBookhoardConfig `json:"bookhoard"`
 	Books          map[string]SidecarBook `json:"books"`
 	Collections    []SidecarCollection    `json:"collections"`
 	OPDSEnabled    bool                   `json:"opds_enabled"`
@@ -30,7 +30,7 @@ type SidecarConfig struct {
 	LastUpdated    string                 `json:"last_updated"`
 }
 
-type SidecarBookmannConfig struct {
+type SidecarBookhoardConfig struct {
 	OPDSCatalog string `json:"opds_catalog"`
 	SyncAPI     string `json:"sync_api"`
 	OPDSBaseURL string `json:"opds_base_url"`
@@ -40,7 +40,7 @@ type SidecarBookmannConfig struct {
 }
 
 type SidecarBook struct {
-	BookhoardUUID     string   `json:"bookhoard_uuid"`
+	BookhoardUUID    string   `json:"bookhoard_uuid"`
 	Title            string   `json:"title"`
 	Author           string   `json:"author"`
 	AvailableFormats []string `json:"available_formats"`
@@ -119,7 +119,7 @@ func (h *SidecarHandler) GetSidecarConfig(c echo.Context) error {
 		}
 
 		books[key] = SidecarBook{
-			BookhoardUUID:     bookUUID,
+			BookhoardUUID:    bookUUID,
 			Title:            item.Title,
 			Author:           author,
 			AvailableFormats: availableFormats,
@@ -169,7 +169,7 @@ func (h *SidecarHandler) GetSidecarConfig(c echo.Context) error {
 	// Build sidecar config
 	config := SidecarConfig{
 		Version: "1.0",
-		Bookmann: SidecarBookmannConfig{
+		Bookhoard: SidecarBookhoardConfig{
 			OPDSCatalog: opdsCatalogURL,
 			SyncAPI:     syncAPIURL,
 			OPDSBaseURL: opdsBaseURL.Value,
@@ -254,7 +254,7 @@ func (h *SidecarHandler) DownloadSidecarConfig(c echo.Context) error {
 		}
 
 		books[key] = SidecarBook{
-			BookhoardUUID:     bookUUID,
+			BookhoardUUID:    bookUUID,
 			Title:            item.Title,
 			Author:           author,
 			AvailableFormats: availableFormats,
@@ -300,7 +300,7 @@ func (h *SidecarHandler) DownloadSidecarConfig(c echo.Context) error {
 
 	sidecarConfig = SidecarConfig{
 		Version: "1.0",
-		Bookmann: SidecarBookmannConfig{
+		Bookhoard: SidecarBookhoardConfig{
 			OPDSCatalog: opdsCatalogURL,
 			SyncAPI:     syncAPIURL,
 			OPDSBaseURL: opdsBaseURL.Value,