Shapes: Tools bar Tool Creates Shape / Mask and Fill / Stroke Options (#227)

The Tools bar had Fill and Stroke swatches and a Stroke Width, kept in
the interface only, so agents couldn't set them and new shapes could
only be a solid fill with a solid stroke. As in After Effects:

- With a shape layer selected and a shape tool or the Pen active, Tool
  Creates Shape / Tool Creates Mask choose whether drawing adds shapes
  to the layer or masks on it (Fill and Stroke hide while drawing
  masks).
- Clicking the word "Fill" or "Stroke" opens Fill Options / Stroke
  Options: None, Solid Color, Linear Gradient or Radial Gradient, the
  blend mode and the opacity. The swatches show the kind; Alt-click
  steps through the kinds.
- New shapes and Pen paths are painted with them: a Gradient Fill or
  Gradient Stroke across the shape for the gradient kinds.

The options are engine state (EditorState.shape_tool) set with the new
shape.toolOptions command; shape.newShape and shape.newPath use them
unless given paint parameters (which now include fillType, fillBlend,
fillOpacity and their stroke twins; layer.newShape takes them too). A
Pen path without paint parameters now takes the Tools bar's stroke
(none by default) instead of a fixed 2 px white one. layer.addMask also
draws rounded rectangle, polygon and star masks, so every shape tool
makes a mask on a selected footage or solid layer (rounded rectangles,
polygons and stars made a new shape layer).

Test: shape_tool_options_paint_new_shapes,
masks_of_every_shape_tool_kind,
tool_creates_mask_draws_a_mask_on_the_selected_shape_layer,
fill_options_paint_the_next_shape.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/control-protocol.md

@@ -114,6 +114,7 @@ Viewer state that agents drive headless too: `view.snapping`, `view.channel {cha
 `view.fastPreviewMode {mode}`, `view.setRegionOfInterest {rect}`, `view.addGuide`,
 `view.moveGuide`, `view.removeGuide`; editing: `shape.newPath` (Pen on shape layers),
 `shape.newShape` (the shape tools: a new group in the selected shape layer, else a new shape layer),
+`shape.toolOptions` (the Tools bar's Tool Creates Shape / Mask and Fill and Stroke Options),
 `mask.insertVertex`, `mask.convertVertex`, `mask.deleteVertices`, `path.freeTransform` (masks and
 shape paths by uid), `keys.setSpatialTangents` (motion-path handles) and `keys.transform` (Graph
 Editor transform box, timeline Alt-drag scaling).