Move items.jsonc under items/, add starter battle/moves.jsonc

Groups item data under assets/items/ to match the cutscenes/ folder
convention, updating itemInit()'s asset path accordingly. Also adds
assets/battle/moves.jsonc as a starting point for move data - there's
no JSON loader consuming it yet (battleability_t is still just a bare
enum), so its field shape is a placeholder rather than a contract.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/dusk/rpg/item/item.c

@@ -34,7 +34,8 @@ errorret_t itemInit(void) {
   ITEM.typeCount = ITEM_TYPE_NULL + 1;
   ITEM.defCount = ITEM_ID_NULL + 1;
 
-  assetentry_t *entry = assetLock("items.jsonc", ASSET_LOADER_TYPE_JSON, NULL);
+  assetentry_t *entry =
+    assetLock("items/items.jsonc", ASSET_LOADER_TYPE_JSON, NULL);
   errorret_t ret = assetRequireLoaded(entry);
   if(errorIsNotOk(ret)) {
     assetUnlockEntry(entry);