fix(styles): use allocate_handle for new style records

Creating a new MLeader/Table/MLine style (and a new PlotSettings) pulled
the document's next handle without advancing the counter, so two records
created in one session collided on the same handle and the second
overwrote the first. Use allocate_handle(), which reserves and advances.

Also bumps acadrust to pick up DXF annotative-flag persistence.

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

Cargo.lock

@@ -54,7 +54,7 @@ checksum = "366ffbaa4442f4684d91e2cd7c5ea7c4ed8add41959a31447066e279e432b618"
 [[package]]
 name = "acadrust"
 version = "0.3.4"
-source = "git+https://github.com/HakanSeven12/acadrust?branch=main#c117f98c3d33dc173e3ee01f39a7729d58bc0347"
+source = "git+https://github.com/HakanSeven12/acadrust?branch=main#d9b9948bad57c6a28a90153d210394f8f695c973"
 dependencies = [
  "ahash",
  "anyhow",
@@ -3176,7 +3176,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b577e2d69827c4740cba2b52efaad1c4cc7c73042860b199710b3575c68438d"
 dependencies = [
  "bytecount",
- "memchr 2.8.1",
+ "memchr 1.0.2",
  "nom 8.0.0",
 ]