Harden parametric sketch constraints

src/app/settings.rs

@@ -221,14 +221,6 @@ pub struct UserSettings {
     pub crosshair_color: Option<[u8; 3]>,
     /// Model-space lineweight preview scale as a percentage.
     pub lineweight_display_scale: i32,
-    /// Whole-interface scale, as a percentage — every panel, dialog, the
-    /// ribbon, and their text, not just one widget's font size. Wired
-    /// straight into iced's own per-window `scale_factor` hook
-    /// (`OpenCADStudio::run`), so a change takes effect immediately with no
-    /// per-panel plumbing needed. Relies on the struct-level `#[serde(default)]`
-    /// (via `impl Default` below) to backfill this field for a config file
-    /// saved before this setting existed, same as every other field here.
-    pub ui_scale: i32,
     /// Isometric drafting changes the grid and crosshair to the active axis pair.
     pub isometric_drafting: bool,
     pub iso_plane: IsoPlane,
@@ -284,13 +276,8 @@ pub struct UserSettings {
     /// When true (default), the app (re)registers itself as a .dwg/.dxf/.bak
     /// handler on every launch. Toggle with the FILEASSOC command.
     pub file_assoc_enabled: bool,
-    /// When true, saving a drawing also writes its sketch constraints as
-    /// AutoCAD's own native object graph (`scene::dwg_native_constraints`),
-    /// not just the app's own XRecord format. Off by default — opt-in, since
-    /// it adds file weight every save whether or not AutoCAD/BricsCAD
-    /// interop is needed. See `write_dwg_native_constraints` on the app
-    /// struct for the full contract (a drawing that already has this native
-    /// graph keeps it synced regardless of this setting).
+    /// When true, saving also writes sketch constraints as native drawing
+    /// objects alongside the application's own persistence record.
     #[serde(default)]
     pub write_dwg_native_constraints: bool,
     /// When true (default), a sketch constraint's viewport pill shows its
@@ -402,7 +389,6 @@ impl Default for UserSettings {
             cursor_type: CursorType::Crosshair,
             crosshair_color: None,
             lineweight_display_scale: 100,
-            ui_scale: 100,
             isometric_drafting: false,
             iso_plane: IsoPlane::Left,
             snap_angle_deg: 0.0,