Add creator field and enriched tooltip for data-driven items

- Add optional "creator" JSON field to display author name in tooltip
- Show body regions, movement style, lock status, and escape difficulty
- Show pose priority and item ID in advanced mode (F3+H)
- Update ARTIST_GUIDE.md field reference and test JSON

src/main/resources/assets/tiedup/tiedup_items/test_handcuffs.json

@@ -1,6 +1,7 @@
 {
   "type": "tiedup:bondage_item",
   "display_name": "Data-Driven Handcuffs",
+  "creator": "TiedUp! Team",
   "model": "tiedup:models/gltf/v2/handcuffs/cuffs_prototype.glb",
   "regions": ["ARMS"],
   "pose_priority": 30,