Live Paint: preserve face colors at shared curved boundaries

Capture sweep-piece source attribution before endpoint pinning can move its
midpoint off the original outlines. Keep the existing lookup after pinning
when the original piece has no source.

Add planar coverage and native compound Make/Expand/undo regressions, and
document the existing front-most source-fill rule.

docs/mcp.md

@@ -1841,7 +1841,9 @@ already walks Image Trace. Short agent entry points:
   `ui.imageTracePresetDialog {params?, rename?}` opens the Image Trace panel's Save as New Preset… or Rename… dialog.
 - Live Paint: `livePaint.make`, `livePaint.merge`, `livePaint.fill {group?, point}`, `livePaint.strokeEdge`,
   `livePaint.info {group}`, `livePaint.release`, `livePaint.expand`, and `livePaint.gapOptions {ids?, detect?, size?,
-  color?, closeGaps?}` (Object › Live Paint › Gap Options). With `detect: true`, paint stops at the gaps that run
+  color?, closeGaps?}` (Object › Live Paint › Gap Options). Make gives each covered face the fill of its front-most
+  covering source, including compound paths with shared curved boundaries. Expand keeps those face fills.
+  With `detect: true`, paint stops at the gaps that run
   from a loose end of a path to the nearest path, up to `size` wide (`small` 3 pt, `medium` 6 pt, `large` 12 pt, or a
   number of points up to 72); `closeGaps: true` adds an unpainted path across each of them. The options are saved with the group, and the reply
   and `livePaint.info` list the gaps up to `size` wide that no path closes, as `[x0, y0, x1, y1]`. `livePaint.merge`

docs/target-app-parity.md

@@ -996,6 +996,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   Object › Live Paint › Merge adds the other selected paths and Live Paint groups to the bottom selected Live Paint group ([Live Paint groups](https://web.archive.org/web/20241230205225/https://helpx.adobe.com/illustrator/using/live-paint-groups.html)), which keeps its id, the paint of its faces and edges, and its name, lock, visibility, transparency, appearance, opacity mask and graphic style link. Object › Live Paint › Make with a Live Paint group selected, and a Live Paint Bucket click on a selected path beside a selected Live Paint group, add the paths to that group the same way. Make, Merge and the Live Paint Bucket take paths, compound paths and groups of them; with type, an image or another object among the selection they report that it has to be converted to paths first and change nothing, as type and raster images can't go into a Live Paint group directly ([Create Live Paint groups](https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/create-live-paint-groups.html)); before, such an object went among the group's hidden sources and vanished from the canvas. Evidence: `tests_build::live_paint_refuses_type_and_images_and_changes_nothing`.
   With the Live Paint Bucket selected, Alt-click on vector art samples its fill, stroke and stroke weight into the paint defaults ([Paint with the Live Paint Bucket tool](https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/paint-with-the-live-paint-bucket-tool.html)). On a placed image it samples the image pixel as a solid fill with no stroke. Alt+Shift-click samples only the color under the pointer, including an intermediate gradient color or image pixels, into the active fill or stroke ([Default keyboard shortcuts](https://helpx.adobe.com/illustrator/using/default-keyboard-shortcuts.html)). Neither click paints or changes the selection or selected art, and the next Bucket click paints with the sampled paint. Evidence: `tests_build::live_paint_bucket_alt_sample_paints_next_face_without_changing_selection`.
   Double-clicking the Live Paint Bucket opens Live Paint Bucket Options ([Paint with the Live Paint Bucket tool](https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/paint-with-the-live-paint-bucket-tool.html)): Paint Fills (on) and Paint Strokes (off) set whether a click paints faces, edges or both, Highlight turns the outline of the face or edge under the pointer on or off, and Color and Width set it (red and 4 px by default). Faces are outlined at the Width and edges at half of it, as the page says faces are highlighted with a thick line and edges with a thin line. With both on, a click paints the edge within 4 px of the pointer, else the face, and Shift switches to Paint Fills only; with one on, Shift switches to the other. The options last across tool switches and are saved with the preferences (`tool.setOption {tool: "livePaintBucket"}`). Evidence: `builder::tests::{bucket_options_choose_what_a_click_paints, bucket_options_set_the_highlight, bucket_highlights_an_edge_thinner_than_a_face}`, `dialogs::live_paint_bucket::tests::double_clicking_the_tool_opens_its_options_and_ok_sets_them`.
+  Live Paint Make preserves the front-most covering source's fill when compound paths share a curved boundary, and Expand keeps the face fills. Regression evidence: `planar::tests::coincident_curves_keep_their_source_faces` checks source order, winding, fill rules and nearby boundaries; `tests::build::live_paint_make_and_expand_keep_abutting_compound_colors` checks native compound paths, Make, Expand and Undo/Redo. This preserves VectorCraft's source-fill rule without changing arrangement precision.
   Live Paint Gap Options (Object › Live Paint › Gap Options…, `livePaint.gapOptions`): with Gap Detection on, paint stops at the gaps that run from a loose end of a path to the nearest path, up to Small (3 pt), Medium (6 pt), Large (12 pt) or a custom size; Close Gaps With Paths adds an unpainted path across each gap; Preview applies the options live and draws the gaps in the Gap Preview Color. The options are saved, copied and undone with the group, and Merge keeps the bottom group's options when its Gap Detection is on, or else turns Gap Detection on with Small when another merged group has it on. When Gap Detection is off in every merged group, it stays off.
   View › Show Live Paint Gaps (`view.livePaintGaps`) draws the gaps of the selected Live Paint groups up to their Paint Stops At size, each in its group's Gap Preview Color, until Hide Live Paint Gaps or Hide Edges hides them ([Live Paint gaps](https://web.archive.org/web/20260105111201/https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/find-and-close-gaps-in-live-paint-groups.html)).
   Double-clicking the Live Paint Selection tool opens its Tool Options ([Live Paint Selection tool options](https://web.archive.org/web/20250904012025/https://helpx.adobe.com/illustrator/using/selecting-objects.html)): with Select Fills off, a click selects an edge instead of a face; with Select Strokes off, Alt-click selects a face instead of an edge; Color and Width set the color and width of the highlight on the face or edge under the pointer (red and 4 px by default). The options last across tool switches and are saved with the preferences (`tool.setOption {tool: "livePaintSelection"}`).