fix(render): match model lineweight preview curve

src/shaders/hatch_texture.wgsl

@@ -23,6 +23,9 @@ struct Uniforms {
 }
 @group(0) @binding(0) var<uniform> u: Uniforms;
 
+const MODEL_LINEWEIGHT_BOOST: f32 = 2.0;
+const MODEL_LINEWEIGHT_MAX_PX: f32 = 10.0;
+
 // ── Group 1: per-hatch data ────────────────────────────────────────────────
 
 struct HatchUniforms {
@@ -117,6 +120,18 @@ struct VOut {
 // `ddx_xz`/`ddy_xz` are screen-space derivatives of `xz`, taken once in
 // fs_main: derivative builtins must run in uniform control flow, and the
 // per-family loop's early return makes later iterations non-uniform.
+fn display_lineweight(width: f32) -> f32 {
+    if u.lineweight_scale < 0.0 {
+        let base = select(
+            min(width * MODEL_LINEWEIGHT_BOOST, MODEL_LINEWEIGHT_MAX_PX),
+            1.0,
+            width <= 1.0,
+        );
+        return max(base * -u.lineweight_scale, 1.0);
+    }
+    return max(width * u.lineweight_scale, 1.0);
+}
+
 fn check_family(
     xz:      vec2<f32>,
     ddx_xz:  vec2<f32>,
@@ -147,11 +162,7 @@ fn check_family(
         -ddx_xz.x * sin_a + ddx_xz.y * cos_a,
         -ddy_xz.x * sin_a + ddy_xz.y * cos_a,
     )) * 0.5;
-    let width_px = select(
-        1.0,
-        max(fam.line_width * u.lineweight_scale, 1.0),
-        u.lwdisplay_enable > 0.5,
-    );
+    let width_px = select(1.0, display_lineweight(fam.line_width), u.lwdisplay_enable > 0.5);
     let half_line = half_px * width_px;
 
     let wpx = length(vec2<f32>(ddx_xz.x, ddy_xz.x));