feat: add ancient artifacts and refactor item categories

Introduce Ancient Artifacts with full CRUD and image support
Migrate item categories and usages to system-defined lists
Add display_id to items and artifacts for custom sorting

frontend/src/icons.ts

@@ -3,6 +3,7 @@ export type AppIcon = string;
 export const iconAdd: AppIcon = 'mdi:plus';
 export const iconAdmin: AppIcon = 'mdi:tune-variant';
 export const iconAction: AppIcon = 'mdi:gesture-tap-button';
+export const iconArtifact: AppIcon = 'mdi:diamond-stone';
 export const iconAutomation: AppIcon = 'mdi:factory';
 export const iconBack: AppIcon = 'mdi:arrow-left';
 export const iconCancel: AppIcon = 'mdi:close';