perf(wire): move LWDISPLAY toggle from CPU rebake to wire shader uniform

LWDISPLAY (Show Lineweight) flipping the toggle no longer triggers a full
retessellate. `render_style_for` always bakes the entity's resolved (layer-
inherited) lineweight, and the wire shader reads `Uniforms.lwdisplay_enable`
to either honour the per-vertex half_width or collapse the quad to a 1 px line.

Side effect: PDF export now uses the real lineweight regardless of LWDISPLAY,
matching AutoCAD's plot semantics (LWDISPLAY only affects screen render).

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

src/app/update.rs

@@ -2514,7 +2514,7 @@ impl H7CAD {
                 if i < self.tabs.len() {
                     let h = &mut self.tabs[i].scene.document.header;
                     h.lineweight_display = !h.lineweight_display;
-                    self.tabs[i].scene.bump_geometry();
+                    // No retessellate — the wire shader reads the flag from uniforms.
                     self.tabs[i].dirty = true;
                 }
                 Task::none()