test(e2e): Playwright regression suite for Studio and Hub, run in CI

[tomasz-zajac-oss]

Summary

Adds an end-to-end regression suite (apps/e2e, Playwright) that drives the production web builds of Studio and Hub, and runs it in the pipeline.

• Coverage (45 tests): welcome screen and sample; editing (palette drop, rename, Alt-drag connect, forbidden relation, undo/redo, delete, reload); static, nested, dynamic, table, treemap, matrix and wiki views; Viewer/Presenter perspectives; presentation playback and slide deep links; PNG/SVG export; Smart Layout invariants (no overlapping siblings, children inside parents, same result on every run); Hub landing, categories, search, concept canvas/wiki/table and .radical download.
• Visual regression: toHaveScreenshot on a frozen page clock, so animations and the live layout render the same frame every run. Baselines are Linux-only, generated in the mcr.microsoft.com/playwright:v1.63.0-noble image. Screenshot assertions are skipped on macOS/Windows; everything else runs there.
• Guards: every test fails on uncaught exceptions or console.error; requests leaving localhost are blocked. Hub's requests to hub.radical.tools are served from this build's out/hub/, so the suite checks the catalogue that is about to ship, not production.
• Pipeline: reusable e2e.yml called from ci.yml; deploy.yml now deploys only after e2e passes. Adding the update-screenshots label to a PR regenerates the baselines in CI and commits them to the branch (only if the suite then passes).
• npm run e2e from the root builds both apps and runs the suite (~1 min locally). Details in apps/e2e/README.md.

Bugs found while writing the suite

Each is a test.fail test in apps/e2e/tests/studio/known-issues.spec.ts (green while the bug exists, red once it's fixed) and is logged in docs/IMPROVEMENTS.md:

1. The live WebCoLa layout never settles in views with nested elements: nodes drift 80–320 px in 10 s (also in the Fintech sample and on Hub concept canvases).
2. Because of that, the 400 ms autosave debounce never fires; edits are saved only on pagehide, together with the drifted positions.
3. Double-click on the empty canvas does not add a system (React Flow's zoomOnDoubleClick swallows it).
4. The Quick Search bar covers Undo/Redo at 1440 px.
5. Hub's local catalogue fallback rejects .radical files served without a JSON content type, so concept deep links fail when hub.radical.tools is unreachable.
6. Property-panel <label>s are not tied to their inputs.

Before merging

The screenshot baselines are not in this PR yet, so the E2E check fails until they are. Add the update-screenshots label, review the committed images, then re-run CI (a bot push does not trigger workflows). Since deploy now depends on e2e, merging without baselines would block deploys.

Type of change

• Tests
• Other: CI pipeline (e2e job, deploy gate, baseline update workflow)

Checklist

• npm test passes
• npm run typecheck passes with no errors
• New or changed behaviour is covered by tests
• Documentation updated if needed (README, CONTRIBUTING, apps/e2e/README.md, docs/IMPROVEMENTS.md)

🤖 Generated with Claude Code