Pet adoption: stop double-deleting pending, pass interaction to resolvePetName

resolvePendingInteraction deletes the pending entry before dispatch, but
resolvePetName then re-ran LoadAndDelete to recover the carried PetType.
That second lookup always missed, so the if !ok branch returned nil: the
save never ran and no pet was ever persisted (adoption was 100% broken).

Pass the already-loaded interaction in, matching every other handler.
Add a regression test driving the real dispatcher path.

internal/plugin/adventure.go

@@ -853,7 +853,7 @@ func (p *AdventurePlugin) resolvePendingInteraction(ctx MessageContext, interact
 	case "pet_type":
 		return p.resolvePetType(ctx)
 	case "pet_name":
-		return p.resolvePetName(ctx)
+		return p.resolvePetName(ctx, interaction)
 	}
 	return nil
 }