feat(lwpolyline): render the wide-polyline band via the wire shader

A wide polyline's flat band was drawn by the hatch pipeline: a solid fill
with only draw-order depth. It ignored the entity linetype (the width
"crushed" the dash pattern) and showed through 3-D geometry in a tilted view.

Draw the band from the polyline's own centre-line wire instead. A new
`WireModel.world_width` (drawing units) makes the wire vertex shader expand
the quad by `world_half_width / world_per_pixel` (clamped to a hairline), so
the band is sized in world units and tracks zoom. Because it is now a wire:

- the GPU dash shader dashes the band by arc-length — the linetype applies;
- it is depth-tested at the polyline elevation — no draw-order see-through;
- no CPU band triangles or per-dash geometry are generated.

`world_half_width` rides in `WireConst` (native, replacing a pad) and the web
`WireInstance` (loc 14); both wire shaders branch on it. The tessellator sets
`world_width` from the LwPolyline width on the Contour / SegmentedLines arms,
and the model-space fill loop no longer emits a hatch band for any LwPolyline.
Pick still uses the band polygon (`pick_tris`).

Blocks keep the hatch band: `LocalWire` carries no `world_width` (finalize
zeroes it), so a scaled insert still scales its band correctly.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/entities/dimension.rs

@@ -1352,6 +1352,7 @@ fn tessellate_dimension_inner(
             let (ext1, ext2) = split_ext_lines(&geom.ext_lines);
             if !ext1.is_empty() {
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -1378,6 +1379,7 @@ fn tessellate_dimension_inner(
             }
             if !ext2.is_empty() {
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -1404,6 +1406,7 @@ fn tessellate_dimension_inner(
             }
         } else {
             wires.push(WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),
@@ -1431,6 +1434,7 @@ fn tessellate_dimension_inner(
     }
 
     wires.push(WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
@@ -1474,6 +1478,7 @@ fn tessellate_dimension_inner(
                     aci_to_rgba(&c)
                 };
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),

src/entities/leader.rs

@@ -590,6 +590,7 @@ impl LeaderTess for Leader {
 
         if verts.len() < 2 {
             return WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),
@@ -696,6 +697,7 @@ impl LeaderTess for Leader {
         }
 
         WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/entities/multileader.rs

@@ -1404,6 +1404,7 @@ impl MultiLeaderTess for MultiLeader {
         // WireModels so the renderer respects per-piece coloring.
         let mut wires: Vec<WireModel> = Vec::new();
         wires.push(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -1693,6 +1694,7 @@ impl MultiLeaderTess for MultiLeader {
                         xy = xy.max(y);
                     }
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1760,6 +1762,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[3],
                     ];
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1795,6 +1798,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[0],
                     ];
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),

src/entities/table.rs

@@ -753,6 +753,7 @@ pub fn tessellate_table(
     let mk =
         |color: [f32; 4], points: Vec<[f32; 3]>, fill_tris: Vec<[f32; 3]>, lw: f32| -> WireModel {
             WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),