fix(multileader): render text properly — strip MText codes, honor full layout

Multileader text was emitted as a single literal stroke pass with no MText
code handling, no rotation, no attachment, no line breaks, no per-piece
color and bad f32 precision under world_offset. Two separate render paths
both had the same bug, and one was masking the fix in the other.

This rewrite, applied to both paths:

- Strips MText format codes (`{\fArial Black|b0|i0|c162|p34;...}`) so the
  rendered text is the actual content, not the markup.
- Honors text_rotation (preferring text_direction so transforms survive),
  text_attachment_point (Left/Center/Right horizontal anchor), and
  text_left_attachment for vertical alignment via a shared
  v_offset_for_attachment helper.
- Splits on \P/\n/\N and word-wraps to text_width.
- Applies line_spacing_factor with the same 5/3 × height convention as
  MText.
- Resolves the text style via text_style_handle (fallback STANDARD).
- Applies ml.scale_factor everywhere (arrow size, dogleg length, text
  height, text width). anno_scale is now only applied when
  enable_annotation_scale is set.
- Splits the scene-level output into separate WireModels so leader,
  text, frame and background fill each carry their own colour
  (ctx.text_color, ml.text_frame, ctx.background_fill_color).
- Mirrors text_direction, base_direction and root.direction in
  apply_transform so a mirrored multileader's text follows the geometry
  instead of staying at its original rotation.
- Computes the text origin and frame corners in offset-relative f32
  space — drawings sit at large absolute coordinates and casting to f32
  before subtracting world_offset was wrecking the rotated sub-glyph
  precision.

src/scene/mod.rs

@@ -3787,6 +3787,25 @@ fn tessellate_entity(
         return wires;
     }
 
+    if let EntityType::MultiLeader(ml) = e {
+        let aabb = entity_aabb(e, world_offset);
+        let mut wires = tessellate::tessellate_multileader(
+            document,
+            h,
+            ml,
+            sel,
+            entity_color,
+            line_weight_px,
+            world_offset,
+            anno_scale,
+        );
+        for w in &mut wires {
+            w.aci = aci;
+            w.aabb = aabb;
+        }
+        return wires;
+    }
+
     if let EntityType::Insert(ins) = e {
         // Resolve the INSERT's own style so ByBlock sub-entities can inherit it.
         let (ins_color, ins_pat_len, ins_pat, ins_lw_px, _) = render::render_style_for(document, e);