search_material stopped on whichever of the character budget or the
100 ms wall-clock budget fired first, but the budget test asserted the
exact character count, so it failed on slow CI runners when the time
budget won (observed scannedChars 786432 instead of 1000000).
Route the search path's clock through the injectable `now` dependency
the wait tool already uses, freeze the clock in the character-budget
test so only that budget can stop the scan, and add a time-budget test
that trips the deadline after exactly one chunk.
Closes#1452
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
