feat(dwg): render section marks from their decoded style and view graph

The section mark's appearance now comes entirely from file data instead
of invented conventions:

- Arrow direction: resolved through the drawing-view graph — the
  symbol's parent AcDbViewRep, the section view (owner of the section
  definition), each view border's active viewport — by projecting the
  section camera's sight onto the parent camera's basis, using the same
  yaw/pitch/twist convention the viewport renderer does. Only when the
  chain is unavailable (DXF, older files) does a geometric fallback
  apply.
- Broken cutting line: driven by the style's plane-line / end-segment
  flags rather than hard-coded.
- Arrowhead: resolved through the shared dimension/leader arrow table
  from the style's arrow block handle; a null handle gives the standard
  ClosedFilled default.
- Label gap: the style's identifier offset.

Bumps acadrust for the style and view-graph decode.

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/OpenAEC-Foundation/acadifc?branch=main#4469ccff930cad39c4edee822772c85021979349"
+source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#8f2cf9543af65353c5fe3f7afbe5139de4ad711c"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",