feat(mtext): integrate every inline format code in MTEXT renderer

Replace the line-based MTEXT pipeline with a run-aware parser + renderer.
Every DXF MTEXT inline code now reaches the stroke output: \H \W \Q \T \A
\C \c \f \F \M \X, the \p block (q/i/l/r/t/s), brace-scoped state, and
the \L\l \O\o \K\k decoration toggles.

Parser ([text_support]): emits Vec<MTextLine{ runs, align, indent_*,
tab_stops }> with per-run RunState; braces scope character state, paragraph
props persist across them.

Renderer ([mtext]): atomise → wrap → render. Per-run height/width/oblique/
tracking/font/colour/decorations/valign; paragraph indents and tab stops
honoured; default 4-em tab fallback.

Plumbing: tessellate() now returns Vec<WireModel>; TextStroke gains an
optional inline-colour override so per-run \C/\c emits one wire per colour.
cxf::tessellate_text_run adds a tracking multiplier. block_cache folds
multi-wire results into a single LocalWire (colour split preserved at
top-level, flattened inside cached defns).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/entities/tolerance.rs

@@ -244,7 +244,7 @@ impl TruckConvertible for Tolerance {
         let origin = [self.insertion_point.x, self.insertion_point.y];
 
         Some(TruckEntity {
-            object: TruckObject::Text(vec![TextStroke { strokes, origin }]),
+            object: TruckObject::Text(vec![TextStroke { strokes, origin, color: None }]),
             snap_pts: vec![(snap_pt, SnapHint::Insertion)],
             tangent_geoms: vec![],
             key_vertices: vec![],