[Amber (YuanboXue-Amber)]

Summary

Fix a race where requestFocus() could still move focus after cancellation, replacement by a newer request, or API disposal when the target was already found.

• Track cancellation until focus is delivered and preserve the canceled status.
• Prevent old handles from canceling newer same-name requests.
• Keep completed requests unchanged when canceled later.

No public API or dependency changes.

Validation

• Added browser regressions for cancellation, replacement, disposal, stale handles, and completed requests.
• ObservedElement + CrossOrigin: 28 tests passed.
• Shadow DOM ObservedElement: 24 tests passed.
• Bundle build, type-check, lint, formatting, and diff checks passed.

[github-actions]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
tabster all exports	110.948 kB 30.14 kB	111.154 kB 30.181 kB	206 B 41 B
tabster getCrossOrigin	107.881 kB 29.426 kB	108.087 kB 29.467 kB	206 B 41 B
tabster getObservedElement	44.334 kB 13.138 kB	44.54 kB 13.183 kB	206 B 45 B

Unchanged fixtures

Package & Exports	Size (minified/GZIP)
tabster createTabster (core)	38.569 kB 11.569 kB
tabster focusable.findAll	38.592 kB 11.577 kB
tabster focusable.findLast	38.593 kB 11.577 kB
tabster focusable.findNext	38.593 kB 11.577 kB
tabster focusable.findPrev	38.593 kB 11.577 kB
tabster getDeloser	47.93 kB 13.853 kB
tabster getGroupper	45.671 kB 13.236 kB
tabster getModalizer	47.596 kB 13.995 kB
tabster getMover	53.128 kB 15.489 kB
tabster getOutline	47.204 kB 13.807 kB
tabster getRestorer	41.154 kB 12.166 kB

_{🤖 This report was generated against cc60426d5ab690bc33f01fb39144f2afd9d3ef0e}