feat(dynamic-input): per-step specs for rectangle, polygon and ellipse

Extend the DynSpec coverage and add the guides those commands need:

- Rectangle: two-corner enters width/height as unsigned magnitudes (the
  sign follows the cursor side, like the angle entry), drawn with the
  rectangle as the guide; rotated rectangle's height is a single distance
  measured square to the base edge (dimension line offset off the edge
  with extension lines); centre rectangle shows half-width/half-height.
- Polygon: inscribed/circumscribed vertex step shows radius + rotation.
- Ellipse: minor-axis step (all three modes) measures the half-length
  perpendicular to the major axis and draws that semi-axis from the
  centre; angle steps anchor their arc at the centre.

Adds DynGuide::Perp / PerpDim (perpendicular measure to a reference line)
and DynSpec::ref_point, plus Width/Height role handling (unsigned display,
cursor-signed commit) and diameter value scaling.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/modules/home/draw/circle.rs

@@ -201,6 +201,7 @@ impl CadCommand for CircleCommand {
                 anchor: DynAnchor::Point(c),
                 fields: vec![DynFieldSpec::new(DynRole::Radius)],
                 guide: DynGuide::Radius,
+                ref_point: None,
             }),
         }
     }
@@ -288,6 +289,7 @@ impl CadCommand for CircleCDCommand {
                 anchor: DynAnchor::Point(c),
                 fields: vec![DynFieldSpec::new(DynRole::Diameter)],
                 guide: DynGuide::Radius,
+                ref_point: None,
             }),
         }
     }

src/modules/home/draw/ellipse.rs

@@ -182,6 +182,31 @@ impl CadCommand for EllipseCommand {
             _ => None,
         }
     }
+
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        match &self.step {
+            // Center + major axis endpoint: ordinary point picks (legacy polar
+            // anchored at the previous point).
+            CtrStep::Center | CtrStep::MajorAxis { .. } => None,
+            // Minor axis: half-length measured square to the major axis. Show
+            // the perpendicular drop from the cursor onto the major axis.
+            CtrStep::MinorRatio { center, major } => Some(DynSpec {
+                anchor: DynAnchor::Point(*center),
+                fields: vec![DynFieldSpec::new(DynRole::Distance)],
+                guide: DynGuide::Perp,
+                ref_point: Some(*center + *major),
+            }),
+        }
+    }
+
+    fn dyn_live_value(&self, cursor: Vec3) -> Option<f64> {
+        if let CtrStep::MinorRatio { center, major } = &self.step {
+            Some((minor_ratio(*center, *major, cursor) * major.length()) as f64)
+        } else {
+            None
+        }
+    }
 }
 
 // ── 2. Axis, End mode ─────────────────────────────────────────────────────
@@ -270,6 +295,30 @@ impl CadCommand for EllipseAxisCommand {
             }
         }
     }
+
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        match &self.step {
+            // Endpoints define the full major axis — legacy polar (anchored at
+            // the previous point) is right.
+            AxisStep::Pt1 | AxisStep::Pt2 { .. } => None,
+            // Minor half-length, square to the major axis.
+            AxisStep::MinorRatio { center, major } => Some(DynSpec {
+                anchor: DynAnchor::Point(*center),
+                fields: vec![DynFieldSpec::new(DynRole::Distance)],
+                guide: DynGuide::Perp,
+                ref_point: Some(*center + *major),
+            }),
+        }
+    }
+
+    fn dyn_live_value(&self, cursor: Vec3) -> Option<f64> {
+        if let AxisStep::MinorRatio { center, major } = &self.step {
+            Some((minor_ratio(*center, *major, cursor) * major.length()) as f64)
+        } else {
+            None
+        }
+    }
 }
 
 // ── 3. Ellipse Arc mode ───────────────────────────────────────────────────
@@ -487,6 +536,38 @@ impl CadCommand for EllipseArcCommand {
             _ => None,
         }
     }
+
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        match &self.step {
+            ArcStep::Center | ArcStep::MajorAxis { .. } => None,
+            // Minor half-length, square to the major axis.
+            ArcStep::MinorRatio { center, major } => Some(DynSpec {
+                anchor: DynAnchor::Point(*center),
+                fields: vec![DynFieldSpec::new(DynRole::Distance)],
+                guide: DynGuide::Perp,
+                ref_point: Some(*center + *major),
+            }),
+            // Start / end sweep angles measured at the centre (the last point
+            // is the previous pick, so anchor the angle arc at the centre).
+            ArcStep::StartAngle { center, .. } | ArcStep::EndAngle { center, .. } => {
+                Some(DynSpec {
+                    anchor: DynAnchor::Point(*center),
+                    fields: vec![DynFieldSpec::new(DynRole::Angle)],
+                    guide: DynGuide::Polar,
+                    ref_point: None,
+                })
+            }
+        }
+    }
+
+    fn dyn_live_value(&self, cursor: Vec3) -> Option<f64> {
+        if let ArcStep::MinorRatio { center, major } = &self.step {
+            Some((minor_ratio(*center, *major, cursor) * major.length()) as f64)
+        } else {
+            None
+        }
+    }
 }
 
 // ── Internal helpers ──────────────────────────────────────────────────────

src/modules/home/draw/shapes.rs

@@ -168,6 +168,21 @@ impl CadCommand for RectCommand {
             [a.x, pt.y, a.z],
         ]))
     }
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        // Opposite corner: enter width and height (signed deltas from the first
+        // corner), with the rectangle drawn as the guide. First corner is a
+        // normal point pick.
+        self.a.map(|a| DynSpec {
+            anchor: DynAnchor::Point(a),
+            fields: vec![
+                DynFieldSpec::new(DynRole::Width),
+                DynFieldSpec::new(DynRole::Height),
+            ],
+            guide: DynGuide::RectSides,
+            ref_point: None,
+        })
+    }
 }
 
 // ── Command: Rectangle — Rotated  (RECT_ROT) ──────────────────────────────
@@ -256,6 +271,29 @@ impl CadCommand for RectRotCommand {
             _ => None,
         }
     }
+
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        // Step 0: corner A (point). Step 1: adjacent corner — the base edge,
+        // needs direction + length (legacy polar). Step 2: height — measured
+        // square to the fixed base edge A→B, so show the perpendicular drop
+        // and take the perpendicular distance (no angle).
+        (self.step == 2).then(|| DynSpec {
+            anchor: DynAnchor::Point(self.b),
+            fields: vec![DynFieldSpec::new(DynRole::Distance)],
+            guide: DynGuide::PerpDim,
+            ref_point: Some(self.a),
+        })
+    }
+
+    fn dyn_live_value(&self, cursor: Vec3) -> Option<f64> {
+        // Live height = perpendicular distance from the cursor to the base edge.
+        (self.step == 2).then(|| {
+            let dir = (self.b - self.a).normalize_or_zero();
+            let perp = Vec3::new(-dir.y, dir.x, 0.0);
+            (cursor - self.b).dot(perp).abs() as f64
+        })
+    }
 }
 
 // ── Command: Rectangle — Center  (RECT_CEN) ───────────────────────────────
@@ -320,6 +358,20 @@ impl CadCommand for RectCenCommand {
             [c.x - hw, c.y + hh, c.z],
         ]))
     }
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        // Corner from the centre gives the half-width / half-height; show them
+        // on dotted axis legs out of the centre.
+        self.center.map(|c| DynSpec {
+            anchor: DynAnchor::Point(c),
+            fields: vec![
+                DynFieldSpec::new(DynRole::Width),
+                DynFieldSpec::new(DynRole::Height),
+            ],
+            guide: DynGuide::AxisDelta,
+            ref_point: None,
+        })
+    }
 }
 
 // ── Command: Polygon — Inscribed  (POLY) ──────────────────────────────────
@@ -359,6 +411,20 @@ impl CadCommand for PolyCommand {
         }
     }
 
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        // Vertex on the circle: radius from the centre + rotation angle.
+        (self.step == 2).then(|| DynSpec {
+            anchor: DynAnchor::Point(self.center),
+            fields: vec![
+                DynFieldSpec::new(DynRole::Radius),
+                DynFieldSpec::new(DynRole::Angle),
+            ],
+            guide: DynGuide::Polar,
+            ref_point: None,
+        })
+    }
+
     fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
         if let Ok(n) = text.trim().parse::<u32>() {
             if (3..=1024).contains(&n) {
@@ -469,6 +535,20 @@ impl CadCommand for PolyCCommand {
         Some(CmdResult::NeedPoint)
     }
 
+    fn dyn_spec(&self) -> Option<crate::command::DynSpec> {
+        use crate::command::{DynAnchor, DynFieldSpec, DynGuide, DynRole, DynSpec};
+        // Edge-midpoint distance (apothem) from the centre + rotation.
+        (self.step == 2).then(|| DynSpec {
+            anchor: DynAnchor::Point(self.center),
+            fields: vec![
+                DynFieldSpec::new(DynRole::Radius),
+                DynFieldSpec::new(DynRole::Angle),
+            ],
+            guide: DynGuide::Polar,
+            ref_point: None,
+        })
+    }
+
     fn prompt(&self) -> String {
         match self.step {
             0 => format!("POLYGON C  Enter number of sides <{}>:", self.sides),