feat(properties): fill placeholder rows from acadrust fields + doc lookups

Bump acadrust to a46cb8b (spline knot parameterization + mtext line-space
style now stored) and populate rows the builders left blank:

Entity-local: spline Knot Parameterization + closed-spline Area (shoelace),
mtext Line space style, hatch Spacing (pattern-line offset), leader Text
offset (annotation offset), region Area + Perimeter (wire-loop approx).

Doc-dependent (resolved in app/properties.rs where the document is
reachable): insert Block Unit + Unit factor (block record units vs
INSUNITS), underlay Name + Path (definition object), leader Text style /
vertical placement / overall scale and tolerance Text style (dimension
style), multileader Max points + segment angles (mleader style).

Rows needing an annotation-scale / sheet-set subsystem or an internal
PDF/DWF layer parser are intentionally left blank.

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

src/entities/hatch.rs

@@ -150,7 +150,15 @@ fn properties(h: &Hatch) -> Vec<PropSection> {
                 ),
                 ro("Layer override", "layer_override", String::new()),
                 ro("Double", "double", if h.is_double { "Yes" } else { "No" }),
-                ro("Spacing", "spacing", String::new()),
+                ro(
+                    "Spacing",
+                    "spacing",
+                    h.pattern
+                        .lines
+                        .first()
+                        .map(|l| format!("{:.4}", l.offset.length()))
+                        .unwrap_or_default(),
+                ),
                 ro("ISO pen width", "iso_pen_width", String::new()),
                 ro("Gradient colors", "gradient_colors", g.colors.len().to_string()),
                 ro("Gradient tint", "gradient_tint", format!("{:.4}", g.color_tint)),