fix(io): trust decoded current layer

Remove the application-side CLAYER fallback now that cadcodec resolves the header handle during document construction.

Refs #743

Cargo.lock

@@ -72,7 +72,7 @@ checksum = "366ffbaa4442f4684d91e2cd7c5ea7c4ed8add41959a31447066e279e432b618"
 [[package]]
 name = "acadrust"
 version = "0.4.1"
-source = "git+https://[email protected]/HakanSeven12/cadcodec.git?rev=2aa1181#2aa1181776b7c1848efe58e3d41ed35138ed7455"
+source = "git+https://[email protected]/HakanSeven12/cadcodec.git?rev=9f3cf8e#9f3cf8e26d5a02fb4ad8ea145ca8e04dd6d6f2bc"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",