No visual regression tests

[xevrion]

The project is mostly layout and has 833 tests, none of which would notice a panel rendering in the wrong place. Several bugs this year were geometry: floating panels not clearing the islands, annotation plates overlapping in stacked rows, a scrollbar squaring off two corners.

A small screenshot comparison over a few examples at a fixed viewport would cover the cases that keep recurring. Worth starting with two or three examples rather than all 23, and covering both themes, since the dark palette is generated and has its own failure modes.

Marking this help wanted rather than good first issue: it needs a tooling decision and CI wiring, not just a patch. Playwright appears in bun.lock today only as a transitive dependency, so adopting it would be a deliberate addition. Worth agreeing the approach on this issue before building it.

[MayurK-cmd]

Hey can i work on this?

[xevrion]

Hey! You asked on four issues at once, so picking one to answer.

This one is yours if you want it. It is self-contained and does not need engine knowledge, which makes it a good first one.

#38 and #15 are closer to each other than they look, both about how load is expressed, and I would rather settle that shape before someone builds either. #55 needs a design call from me first.

One at a time works better here anyway, for you as much as for review.

[MayurK-cmd]

One at a time starting from this