Add AbortController to cancel in-flight search requests when a new
search fires, preventing stale results from overwriting newer ones.
The controller is also aborted on component unmount for cleanup.
Switched from apiGet to apiRequest to support passing AbortSignal.
Added 3 new tests verifying signal passing, abort on new search,
and abort on unmount.
Co-Authored-By: Claude Opus 4.6 <[email protected]>