Add-ons: Parametric Shape Tool — re-editable stars, polygons, rings, arrows, gears and more

Path Precision Tools gains the Parametric Shape Tool: ten kinds of shape
(rectangle, ellipse, polygon, star, ring, arrow, cross, heart, gear,
speech bubble) that stay editable as numbers.

- Geometry in vectorcraft_pathops::addons::pathtools::shapes: each kind's
  outline, corner rounding limited to the middle of a side, a fingerprint
  of the outline, recovery of centre, size and rotation after a move,
  turn or scale, and recognition of plain rectangles, ellipses and
  regular polygons.
- The tool (parametricShape, All Tools drawer and Object › Plug-ins ›
  Path Precision Tools only, no shortcut): drag from the centre (Shift:
  45° steps), arrow keys change the count and values while dragging,
  handles edit a selected shape, double-click places one.
- Commands addon.pathtools.shape.create / .set / .convert, one undo step
  each; params checked (counts 3..1000, sizes up to 16384 pt).
- A shape keeps its numbers in one object-data entry (vc-pathtools-shape)
  that SVG export already leaves out; anchor edits make it a plain path.
- Parametric Shape panel, cursor stand-in, catalog rows in all 25
  languages, docs and tests.

crates/engine/tests/command_sweep.rs

@@ -510,6 +510,20 @@ fn structured_junk() {
         ("shapeBuilder.regions", json!({"ids": [2, 3], "gap": "x"})),
         ("shapeBuilder.regions", json!({"gap": true})),
         ("shapeBuilder.regions", json!({"gap": 12, "ids": [u64::MAX]})),
+        // Path Precision Tools: the Parametric Shape Tool.
+        ("addon.pathtools.shape.create", json!({"center": [1e308, -1e308], "width": 1e308, "count": 1e308})),
+        (
+            "addon.pathtools.shape.create",
+            json!({"center": [0, 0], "kind": "gear", "count": 1000, "a": 0.9, "radius": 16384, "width": 16384, "height": 0.01}),
+        ),
+        ("addon.pathtools.shape.create", json!({"center": [0, 0], "kind": "star", "count": 1000, "a": 0.01, "radius": 1e-300})),
+        ("addon.pathtools.shape.create", json!({"center": ["x", null], "kind": ["star"], "rotation": f64::NAN})),
+        ("addon.pathtools.shape.create", json!({"center": [5, 5], "kind": "bubble", "a": -1e308, "b": 1e308, "rotation": 1e308})),
+        ("addon.pathtools.shape.set", json!({"id": 2, "count": 1000, "kind": "gear"})),
+        ("addon.pathtools.shape.set", json!({"id": u64::MAX, "width": -1})),
+        ("addon.pathtools.shape.set", json!({"id": 2, "center": [1, 2, 3], "radius": "big"})),
+        ("addon.pathtools.shape.convert", json!({"ids": [0, 1, 2, 3, u64::MAX]})),
+        ("addon.pathtools.shape.convert", json!({"ids": "all"})),
         // Smart Pen add-on.
         ("addon.pen.append", json!({"id": 2, "x": 1e308, "y": 0, "in": [1e308, -1e308]})),
         ("addon.pen.append", json!({"id": 2, "subpath": u64::MAX, "x": 0, "y": 0, "segment": "curved"})),