fix(mleader): honour the baked context — anchors, rotation, dogleg, frames

The annotation context is AutoCAD's baked display state; the renderer
now trusts it instead of re-deriving:

- text_attachment_point (L/C/R) is the stored horizontal anchor — the
  leader-side guess shifted centre/right-attached texts by their width.
- ctx.text_direction/text_rotation apply as stored; forcing the
  Horizontal angle type to 0 un-rotated angled leaders. The conn.y
  baseline snap now applies only to unrotated text.
- The dogleg runs along the leader root's stored direction (angled
  leaders drew it world-horizontal), and vertically-attached leaders
  draw no dogleg at all.
- Underline attachments (BottomLine / BottomOfTopLineUnderline…) draw
  the leader-coloured rule under the attached line(s), full text width.
- Vertical text flow (ctx.text_flow_direction) feeds the shared
  vertical layout; frame/background boxes wrap the laid-out glyph
  bounds padded by ctx.landing_gap, and run-less decoration strokes +
  inline \C colours reach the output instead of being dropped.
- The wrap-width grip rides the shared flow_grip_axis() (rotation, flow
  and attachment side), and its drag projects on the same axis.

acadrust bump: every MULTILEADER decodes (has_ds peek), MTEXT
top-to-bottom direction reads correctly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Cargo.lock

@@ -74,7 +74,7 @@ checksum = "366ffbaa4442f4684d91e2cd7c5ea7c4ed8add41959a31447066e279e432b618"
 [[package]]
 name = "acadrust"
 version = "0.4.0"
-source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#4ef83a122446504a988ed8ed7904b1c1b5f1b51f"
+source = "git+https://github.com/OpenAEC-Foundation/acadifc?branch=main#1497d7ab8be725e0bed84ce31e85fa20646ddc51"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",