fix: apply global LTSCALE to linetype pattern rendering

Entity linetype_scale is a per-entity multiplier applied on top of the
document-level $LTSCALE header variable. The previous code used only the
entity scale (defaulting to 1.0), ignoring $LTSCALE entirely. Drawings
with a non-default LTSCALE showed dash patterns at the wrong size.

Effective scale is now: document.header.linetype_scale * entity linetype_scale.
Applied in both render::render_style_for and the complex-linetype path in
tessellate_entity.

Fixes part of #10

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/scene/mod.rs

@@ -3115,7 +3115,7 @@ fn tessellate_entity(
     let (entity_color, pattern_length, pattern, line_weight_px, aci) =
         render::render_style_for(document, e);
     let entity_color = render::adapt_to_bg(entity_color, bg_color);
-    let lt_scale = e.common().linetype_scale as f32;
+    let lt_scale = document.header.linetype_scale as f32 * e.common().linetype_scale as f32;
     let lt_name = render::linetype_name_for(document, e);
 
     if let EntityType::Dimension(dim) = e {

src/scene/render.rs

@@ -213,7 +213,8 @@ pub(super) fn render_style_for(
     };
 
     let lt_name = linetype_name_for(document, e);
-    let lt_scale = e.common().linetype_scale as f32;
+    // Effective scale = global LTSCALE × per-entity scale (both default to 1.0).
+    let lt_scale = document.header.linetype_scale as f32 * e.common().linetype_scale as f32;
     let (pattern_length, pattern) = resolve_pattern(&document.line_types, lt_name, lt_scale);
 
     let line_weight_px = {