feat(community-pets): add dentist mascot (#1924)

A friendly stylized chibi dentist in white scrubs and surgical mask.
8x9 atlas (1536x1872 webp) covering idle, run-left/right, waving,
jumping, failed, waiting, running, review states.

assets/community-pets/dentist/pet.json

@@ -0,0 +1,10 @@
+{
+  "id": "dentist",
+  "displayName": "Dentist",
+  "description": "A friendly stylized chibi dentist mascot in white dental scrubs and surgical mask.",
+  "spritesheetPath": "spritesheet.webp",
+  "author": "mario",
+  "tags": [],
+  "source": "local-hatch",
+  "sourceUrl": ""
+}