feat: use authored category names for mods

Complete the category-array migration while preserving the authored category names. Keep version requirements in their separate commit.

manifest.json

@@ -4,7 +4,7 @@
   "version": "0.1.0",
   "author": "ct",
   "description": "A test fixture, not content: property patches the property_patches test loads to check how patches of other mods' characters and items merge. Never part of a game.",
-  "category": "other",
+  "categories": ["other"],
   "depends": [
     "cthangover_game>=0.1.0",
     "cthangover_murakami>=0.1.0",