Rename project module and database references: Bookmann → Bookhoard

Core infrastructure changes:
- Update Go module name: bookmann → bookhoard
- Rename database schema references and comments
- Update database column names: bookmann_uuid → bookhoard_uuid
- Rename SQL query functions: GetDeviceCatalogByBookmannUUID → GetDeviceCatalogByBookhoardUUID
- Update configuration defaults

This is part 1 of the project rename to Bookhoard.

internal/database/models.go

@@ -32,7 +32,7 @@ type DeviceCatalogs struct {
 	ID             pgtype.UUID        `db:"id" json:"id"`
 	DeviceID       pgtype.UUID        `db:"device_id" json:"device_id"`
 	MediaItemID    pgtype.UUID        `db:"media_item_id" json:"media_item_id"`
-	BookmannUuid   pgtype.UUID        `db:"bookmann_uuid" json:"bookmann_uuid"`
+	BookmannUuid   pgtype.UUID        `db:"bookhoard_uuid" json:"bookhoard_uuid"`
 	KoboContentID  string             `db:"kobo_content_id" json:"kobo_content_id"`
 	ContentIDType  pgtype.Text        `db:"content_id_type" json:"content_id_type"`
 	Available      pgtype.Bool        `db:"available" json:"available"`