The "cancels a pending debounce timer when the input is re-focused" test
passed trivially after the delay:null change: synchronous typing meant the
assertion ran at t≈0, before the 300ms debounce could ever fire, so it
passed whether or not handleFocus's clearTimeout worked.
Rewrote it with fake timers so the debounce window elapses deterministically
(advance the clock by 400ms directly). The interaction is driven with
fireEvent rather than userEvent because userEvent's async internals deadlock
under vitest fake timers with the Mantine/happy-dom stack. Verified
load-bearing: removing the clearTimeout in handleFocus makes it fail
(expected 1 to be 0), and it passes once restored.
Also tightened the sibling-context comment (with delay:null the sibling is
reliably "es"); the tolerant /^es?$/ regex is left as-is.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S3fTN8H3R8YV4yUGvZjYnX
dd7812063c