Review found that two different matches with the same file name collided
in Icarus's folder: the second replaced the first, or kept the old bytes
under the new header. Added copies are now named after the match id the
header names. Adds run one at a time so overlapping drops can't both
decide a match is new, a load that finishes after a newer one is dropped,
an unreadable file no longer counts as having its match, and a reveal
waits for a listing that has its replays and gathers others still waiting.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>