Two fixes:
1. cmdThreadRemove: always call both removeThreadEntry and
removeThreadHistoryEntries regardless of resolved source,
preventing race where thread moves from active to history
between resolve and delete.
2. Test: add waitUntilRunningFileAbsent before thread show/rm,
matching the pattern used by adjacent test cases.
Verified 5x consecutive runs with 0 failures.
Closes#265
xiaoju
942ff4b1a4