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/queries/queries.sql

@@ -1388,8 +1388,8 @@ DO UPDATE SET
     delivery_method = EXCLUDED.delivery_method
 RETURNING *;
 
--- Get device catalog by Bookmann UUID
--- name: GetDeviceCatalogByBookmannUUID :one
+-- Get device catalog by Bookhoard UUID
+-- name: GetDeviceCatalogByBookhoardUUID :one
 SELECT * FROM device_catalogs WHERE device_id = $1 AND bookmann_uuid = $2;
 
 -- Get device catalog by Kobo ContentId