chore(deps): bump acadrust — surface class-based entities the reader can't type

Pulls acadrust 769741d: the classes reader never derived is_an_entity from
item_class_id, so the flag was false for every class and any class-based entity
without an explicit type mapping was decoded as an object and dropped. Drawings
carrying an application's custom entity silently lost it.

Surfaces such entities as EntityType::Unknown with their raw record and proxy
graphics, so the renderer can fall back to the cached outline the way AutoCAD
does for an object whose enabler is absent.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

Cargo.lock

@@ -73,7 +73,7 @@ checksum = "366ffbaa4442f4684d91e2cd7c5ea7c4ed8add41959a31447066e279e432b618"
 [[package]]
 name = "acadrust"
 version = "0.4.0"
-source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#dd4a4dc44dd84fe52d353e555895b268ac03e274"
+source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#769741db529601ada625570710db7ed56f2cecd6"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",