M3.41: Stroke panel follows Units > Stroke, shows mixed values blank and reaches the Control bar

- Weights and dash lengths show in Units > Stroke in the Stroke panel,
  the Control bar and the Properties panel (Session::stroke_unit).
- Values the selected objects don't share show blank (weight, miter
  limit, dashes) or light no button (cap, join, align), from a
  per-revision cached DocState::stroke_mixed.
- Align Stroke Inside/Outside are disabled for open paths and type.
- The Control bar weight is a preset spinner with a width profile
  dropdown, and its Stroke link (and the Properties panel's) opens the
  Stroke panel as an anchored popover instead of docking it.
- The panels show a group's first painted object's stroke, as the
  Stroke proxy does (Session::shown_stroke).
- stroke.set on a group skips images and symbol instances.
- document.inspect reports each object's strokeOptions (cap, join,
  miterLimit, align, dash, dashOffset, alignDashes, arrows, arrowAlign,
  profile) in stroke.set terms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/mcp.md

@@ -332,4 +332,5 @@ options go to every run (the object keeps no stroke of its own); an `item` still
 with `appearance.addStroke`, which takes every stroke option (dashes, profile, opacity, blend) like a path's and paints under or over the
 characters as its place relative to the Characters row says. To stroke
 some characters, use `text.setRangeStyle {id, start, end, strokeOptions: {weight?, cap?, join?, miterLimit?, dash?,
-dashOffset?, alignDashes?}}`.
+dashOffset?, alignDashes?}}`. `inspect_document` reports each object's stroke as `strokeOptions` (type: its first
+run's) in `stroke.set` terms. `stroke.set` on a group leaves the images and symbol instances in it alone.