Two legibility fixes for the canvas z-order menu, from user feel-testing:
- z-only commits no longer remount the preview iframe. The commit hook
already applies the inline z (+ injected position) to the live elements and
updates the store synchronously; the post-commit reloadPreview() was a
redundant full remount that read as a canvas 'blink' on every action.
commitDomEditPatchBatches gains skipReload, engaged only when provably
safe: every op is an inline-style patch AND the server reports every patch
matched — anything else falls back to the reload so the preview reconverges
with disk. The file-watcher's own reload stays suppressed by the existing
domEditSaveTimestampRef window, so the skip is real.
- Bring Forward / Send Backward step over the next VISIBLY overlapping
sibling. The nearest z-neighbor in a composition is often invisible at the
current frame (runtime hides time-inactive clips with inline
visibility/display; GSAP parks elements at opacity 0), so the step crossed
something the user couldn't see — 'enabled but nothing happens'. The
forward/backward set now filters on element-level computed visibility
(display/visibility/opacity, injectable for tests); enable/disable shares
the resolver so the menu is honest: actions disable when no visible
neighbor exists. Front/back keep the full painting family.
- The neighbor that was stepped over gets a 600ms accent flash, drawn in the
studio overlay layer (never in the iframe DOM), so the action shows its
work.
