chore(properties): remove dead helpers left by property-builder rewrite

The spec-conforming property builders dropped the rows that used these
helpers, leaving them unreferenced: hookline_dir_str (leader),
length_and_area (lwpolyline), render_mode_label / STD_VIEWS /
viewport_view_label (viewport). No behavior change.

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

src/entities/leader.rs

@@ -184,13 +184,6 @@ fn creation_type_str(ct: &LeaderCreationType) -> &'static str {
     }
 }
 
-fn hookline_dir_str(hd: &HooklineDirection) -> &'static str {
-    match hd {
-        HooklineDirection::Opposite => "Opposite",
-        HooklineDirection::Same => "Same",
-    }
-}
-
 fn color_str(c: &acadrust::types::Color) -> String {
     match c.rgb() {
         Some((r, g, b)) => format!("RGB({},{},{})", r, g, b),

src/entities/lwpolyline.rs

@@ -359,44 +359,6 @@ fn properties(pline: &LwPolyline) -> Vec<PropSection> {
     ]
 }
 
-/// Path length and enclosed area of a polyline, accounting for arc
-/// (bulge) segments. Length is the actual path — it excludes the implicit
-/// closing segment when the polyline is open. Area always treats the
-/// polyline as closed (last vertex joined back to the first), matching how
-/// CAD property panels report a polyline's area.
-fn length_and_area(pline: &LwPolyline) -> (f64, f64) {
-    let n = pline.vertices.len();
-    if n < 2 {
-        return (0.0, 0.0);
-    }
-    let mut length = 0.0;
-    let mut chord_area = 0.0; // shoelace over chords, signed
-    let mut arc_area = 0.0; // bulge corrections, signed
-    for i in 0..n {
-        let v0 = &pline.vertices[i];
-        let v1 = &pline.vertices[(i + 1) % n];
-        let p0 = [v0.location.x, v0.location.y];
-        let p1 = [v1.location.x, v1.location.y];
-        // The wrap edge (last → first) is part of the closed-area shoelace
-        // regardless, but only contributes to length when the polyline is
-        // actually closed.
-        chord_area += p0[0] * p1[1] - p1[0] * p0[1];
-        let is_wrap = i + 1 == n;
-        if is_wrap && !pline.is_closed {
-            continue;
-        }
-        let chord = ((p1[0] - p0[0]).powi(2) + (p1[1] - p0[1]).powi(2)).sqrt();
-        match crate::entities::common::BulgeArc::from_bulge(p0, p1, v0.bulge) {
-            Some(arc) => {
-                length += arc.radius * arc.sweep.abs();
-                arc_area += 0.5 * arc.radius * arc.radius * (arc.sweep - arc.sweep.sin());
-            }
-            None => length += chord,
-        }
-    }
-    (length, (chord_area / 2.0 + arc_area).abs())
-}
-
 fn apply_geom_prop(pline: &mut LwPolyline, field: &str, value: &str) {
     let Some(v) = parse_f64(value) else {
         return;

src/entities/viewport.rs

@@ -68,15 +68,6 @@ const RENDER_MODES: &[(&str, ViewportRenderMode)] = &[
     ),
 ];
 
-fn render_mode_label(mode: &ViewportRenderMode) -> &'static str {
-    for (label, m) in RENDER_MODES {
-        if m == mode {
-            return label;
-        }
-    }
-    "2D Wireframe"
-}
-
 // ── Shade plot mode labels ────────────────────────────────────────────────
 
 const SHADE_PLOT_LABELS: &[&str] = &["As Displayed", "Wireframe", "Hidden", "Rendered"];
@@ -88,21 +79,6 @@ fn shade_plot_label(mode: i16) -> &'static str {
         .unwrap_or("As Displayed")
 }
 
-// ── Standard view options ─────────────────────────────────────────────────
-
-const STD_VIEWS: &[&str] = &[
-    "Top",
-    "Bottom",
-    "Front",
-    "Back",
-    "Left",
-    "Right",
-    "SW Isometric",
-    "SE Isometric",
-    "NE Isometric",
-    "NW Isometric",
-];
-
 fn grips(vp: &Viewport) -> Vec<GripDef> {
     let (cx, cy, cz) = (vp.center.x, vp.center.y, vp.center.z);
     let hw = vp.width / 2.0;
@@ -212,47 +188,6 @@ fn properties(vp: &Viewport) -> Vec<PropSection> {
     ]
 }
 
-/// Identify which standard view matches the viewport's view direction.
-fn viewport_view_label(vp: &Viewport) -> String {
-    let d = &vp.view_direction;
-    let dx = d.x;
-    let dy = d.y;
-    let dz = d.z;
-
-    // Use a simple threshold comparison to classify the view direction.
-    if dx.abs() < 0.1 && dy.abs() < 0.1 && dz > 0.5 {
-        return "Top".into();
-    }
-    if dx.abs() < 0.1 && dy.abs() < 0.1 && dz < -0.5 {
-        return "Bottom".into();
-    }
-    if dx.abs() < 0.1 && dy < -0.5 && dz.abs() < 0.1 {
-        return "Front".into();
-    }
-    if dx.abs() < 0.1 && dy > 0.5 && dz.abs() < 0.1 {
-        return "Back".into();
-    }
-    if dx < -0.5 && dy.abs() < 0.1 && dz.abs() < 0.1 {
-        return "Left".into();
-    }
-    if dx > 0.5 && dy.abs() < 0.1 && dz.abs() < 0.1 {
-        return "Right".into();
-    }
-    if dx < -0.4 && dy < -0.4 && dz > 0.4 {
-        return "SW Isometric".into();
-    }
-    if dx > 0.4 && dy < -0.4 && dz > 0.4 {
-        return "SE Isometric".into();
-    }
-    if dx > 0.4 && dy > 0.4 && dz > 0.4 {
-        return "NE Isometric".into();
-    }
-    if dx < -0.4 && dy > 0.4 && dz > 0.4 {
-        return "NW Isometric".into();
-    }
-    "Custom".into()
-}
-
 fn apply_geom_prop(vp: &mut Viewport, field: &str, value: &str) {
     use acadrust::types::Vector3;