Measure: centre-to-centre for holes, diameters for circles and arcs, slot sizes (#1392) (#1419)

Measure now reads the picked item's exact shape (cylindrical faces, circular and arc edges,
sketch circles, arcs and lines, profiles, planes, points):

- A circle, hole or arc shows Ø, R and its length (circumference, or arc length and angle).
- A slot (a sketch profile, or a half-cylinder end of a slot in a solid) shows its width,
  centre-to-centre length and overall length.
- Two items where one is round measure from the centre or axis by default (axis to axis,
  axis to plane, edge or point), with the closest and farthest distances listed too; the
  panel switches between centre, min and max, and the canvas line follows.
- inspect.measure and MCP `measure` (new `items` argument) add diameter, radius,
  center_distance, min and max; existing fields are unchanged.

Co-authored-by: Claude Opus 5.5 <[email protected]>

docs/mcp.md

@@ -146,7 +146,7 @@ They cover the workflow, the command shapes, how to verify with `measure`, and t
 | `execute` | `command`, `params?`, `verbose?` (default true) | Run any command with JSON parameters (`list_commands` shows them). Failures leave the design unchanged. A feature command replies with the feature (`feature`, `name`), every body (`bodies`) and the bodies it created, changed and removed (`created_bodies`, `changed_bodies`, `removed_bodies`). `verbose: false` uses the same compact reply as `batch`. |
 | `batch` | `commands: [{command, params}]`, `rollback?` (default true), `verbose?` (default true) | Run steps in order, stop at the first error and undo the completed steps. The reply names the failing step (`failed.index`, `failed.command`, `failed.error`) and every result before it. `verbose: false` keeps the reply small in large designs: feature steps leave out the full body list (`created_bodies`, `changed_bodies`, `removed_bodies` stay) and sketch steps the ids they repeat outside `created`. Bridged to an app that has `engine.batch`, the whole batch is one control request (one frame of the app). Older apps, and apps showing the agent cursor, get the steps one by one. |
 | `inspect_design` | `measure?` (default true), `sketches?` (default true) | Design properties (`metadata`: project, author… and other tools' keys; set them with `execute` `document.metadata.set`), parameters, timeline (type, suppressed, rolled back, error, warning, timing), bodies (volume, area, centre of mass, bbox, face/edge/vertex counts, visible; `removed_later: true` while a sketch is being edited on a rolled-back timeline and a later feature deletes the body, which is then not shown), sketches (curves, points, constraints, profiles, DOF, solve status, visible), selection, undo depth. Hide helper sketches, bodies or construction planes with `execute` `browser.visibility` (`{items, visible}` or `{folder, visible}`), and joint glyphs with `{joints: [id or name], visible}` or `{folder: "joints", visible}` (a hidden joint still constrains and drives; `joint.list` reports each joint's `visible`). |
-| `measure` | `body?` | Volume (mm³), area (mm²), centre of mass, bbox and topology counts per body, with totals. |
+| `measure` | `body?` or `items?` | Volume (mm³), area (mm²), centre of mass, bbox and topology counts per body, with totals. With `items` (one or two selections as `execute` takes them: `face`, `edge`, `vertex`, `sketch_curve`, `profile`), the picked geometry instead: see below. |
 | `body_topology` | `body` | Edges (index, midpoint, length, ends) and faces (index, name, area, centroid, normal, `point`, and for a cylindrical face its `cylinder`: `origin`, `axis`, `radius`). An edge midpoint is the `[x,y,z]` that picks that edge for fillet and chamfer. A face's `point` lies on it and picks it (its centroid may not: that of a face with a hole is in the hole); a face's `name` picks it for the commands that take faces (`face.delete`, `solid.shell`, `solid.draft`, `solid.offset_face`, `solid.split_face`, `solid.replace_face`, and `face` of `sheet.convert`). |
 | `set_parameter` | `name`, `value` (number or expression), `unit?`, `comment?` | Create or change a user parameter and recompute; reports `recomputed` (features rebuilt), `restored` (features whose earlier result for the same inputs was reused, e.g. a value set back) and features that now fail. |
 | `screenshot` | `view?` (iso, top, front, back, bottom, left, right, home, fit, or a named view saved with `view.save`), `camera?` (`{target, yaw, pitch, distance, fov?}`, as `view.apply`), `path?`, `width?`, `height?`, `source?` (window, model), `grid?`, `axes?` | A PNG image content block. Headless: CPU render fitted to the model, or from the named view or camera. Bridged: the app window (default) or a model render with the app's camera; a named view or camera moves the app's viewport there first (`execute` `view.apply` does the same without a screenshot). `grid: false` and `axes: false` leave the ground grid (it lies on Z 0 and cuts through a part that straddles it) and the origin's axes out of a model render; axes hidden with `browser.visibility` stay out whatever `axes` says. Bridged, a screenshot that gives `grid` or `axes` is a model render, which follows the app's Grid and Origin switches for what it does not give; `source: "window"` with either is an error. |
@@ -157,6 +157,24 @@ They cover the workflow, the command shapes, how to verify with `measure`, and t
 | `open` | `path` | Open a `.solidcraft` design, a STEP file (`.step`/`.stp`) as a new design holding its bodies (an Import base feature), or a 3MF/STL file as mesh bodies. |
 | `save` | `path?` | Save the design (to its current file without `path`). |
 
+`measure` with `items` reports each item under `items` (`length_mm`, `area_mm2` or `position`).
+A circle, arc, hole or other cylindrical face also gives `diameter`, `radius`, `center` and
+`axis`, with `circumference` when it goes all the way round, or `arc_length` and `angle_deg`
+for an arc; `round` says which (`circle`, `arc`, `cylinder`). A slot (a sketch profile of two
+half circles and two lines, or one half-cylinder end of a slot in a solid) gives `slot`:
+`width`, `center_distance` and `overall_length`. With one item these fields are repeated at
+the top level. With two items:
+
+- `min` (also `distance_mm`, with `from`, `to` and `delta`): the closest distance;
+- `max` (with `max_from`, `max_to`): the farthest distance;
+- `center_distance` (with `center_from`, `center_to`): when an item is round, from its centre
+  or axis: axis to axis for parallel axes, the closest distance between the axes otherwise,
+  and axis to plane, line or point;
+- `measure`: the distance the Measure panel shows first (`center` where there is one, else `min`);
+- `angle_deg` between two planar faces or straight edges.
+
+Earlier fields are unchanged, so older scripts keep working.
+
 To change a feature after it is made, read its definition with `execute` `timeline.inspect`
 (`{feature}`: id or name) and change fields with `timeline.edit` (`{feature, set}`; e.g.
 `{"extent": {"distance": "30"}}`). The fields per feature type are listed in the book's