build(deps): compile acadrust from the OpenAEC-Foundation/acadifc fork

Point the acadrust patch at the OpenAEC-Foundation/acadifc fork (still the
`acadrust` crate). Its main carries the Arc copy-on-write entity storage that
makes the undo document clone O(entities) refcount bumps instead of a full deep
copy — cutting the per-edit snapshot on a 788k-entity drawing from ~1.7s to
~70ms. No source changes here: acadrust`s public API is unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Cargo.lock

@@ -73,7 +73,7 @@ checksum = "366ffbaa4442f4684d91e2cd7c5ea7c4ed8add41959a31447066e279e432b618"
 [[package]]
 name = "acadrust"
 version = "0.4.0"
-source = "git+https://github.com/HakanSeven12/acadrust?branch=main#d1e198b66db8a460915d7ebcdb293e912d7bf964"
+source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#a7f4741eb9dbcc8f44170eca3a5c85143b6cf432"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",
@@ -3178,7 +3178,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b577e2d69827c4740cba2b52efaad1c4cc7c73042860b199710b3575c68438d"
 dependencies = [
  "bytecount",
- "memchr 1.0.2",
+ "memchr 2.8.2",
  "nom 8.0.0",
 ]