feat(styles): green ✓ for current style + resolve it from DWG files

- The current-style marker is now a green ✓ in its own fixed-width column
  so names stay aligned; rendered as a separate coloured glyph rather than
  baked into the label string.
- Resolve the current text / dimension / multiline style from the handle
  the DWG header stores into the name the app reads (fix_current_style_names
  on load). DXF already provides these as names ($TEXTSTYLE / $DIMSTYLE /
  $CMLSTYLE); DWG only stores handles, so the marker previously always fell
  back to "Standard". Only overrides when the handle resolves.

Note: table and multileader current styles are not surfaced by the file
reader (no header name/handle exposed), so those markers still default to
the app's active selection until acadrust exposes them.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui/style_manager.rs

@@ -114,16 +114,10 @@ pub fn view<'a, 'b>(s: Scaffold<'a, 'b>) -> Element<'a, Message> {
         .iter()
         .map(|name| {
             let is_sel = name.as_str() == s.selected;
-            // Mark the current style with a leading ✓; pad the rest so names
-            // line up.
-            let label = if s.current == Some(name.as_str()) {
-                format!("✓ {name}")
-            } else {
-                format!("    {name}")
-            };
+            let is_current = s.current == Some(name.as_str());
             crate::ui::style_list::item(
                 name,
-                label,
+                is_current,
                 is_sel,
                 s.kind,
                 (s.on_select)(name.clone()),