feat(properties): audit editable vs read-only across all entities

Reclassify every property row to match standard palette behaviour: a row
is editable only when its value maps directly to a stored field AND its
apply_geom_prop handler is wired; computed/derived/count/handle/
cross-object values stay read-only.

Newly editable (all apply-wired): attribute tag/prompt; ellipse major
radius; hatch Double; lwpolyline closed/linetype-gen; mline style;
multileader annotative/landing/background-fill; polyline 2D+3D vertex
coords/segment widths/linetype-gen; shape style; spline control/fit
point coords, weight, fit tolerance, tangents; table break-option flags;
text alignment point, upside-down, backward; underlay display flags.

Corrections: spline Degree -> read-only (editing desynced the knot
vector); removed a duplicate leader "Arrowhead" row.

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

src/entities/mline.rs

@@ -211,7 +211,11 @@ impl PropertyEditable for MLine {
             PropSection {
                 title: "Misc".into(),
                 props: vec![
-                    ro("Style", "ml_style", self.style_name.clone()),
+                    Property {
+                        label: "Style".into(),
+                        field: "ml_style",
+                        value: PropValue::EditText(self.style_name.clone()),
+                    },
                     Property {
                         label: "Style justification".into(),
                         field: "ml_justification",
@@ -249,6 +253,10 @@ impl PropertyEditable for MLine {
                 };
                 return;
             }
+            "ml_style" => {
+                self.style_name = value.to_string();
+                return;
+            }
             _ => {}
         }
         let Ok(v) = value.trim().parse::<f64>() else {