A tick runs its top cards in one wave, handing out worker runs in priority order (at most TIME_VENTURE_HEAVY, default 3; one per card per tick). Made safe for threads: the folder lock is a per-build Hands subclass instead of a patch on the shared class, ventures.json is read fresh and written under a lock, and a contents PUT that loses the race for the branch head (409) is retried. TIME_VENTURE_HEAVY=1 is the old one-at-a-time. Claude-Session: https://claude.ai/code/session_01VDkN7ukK1kXkqov8FaZxva Co-authored-by: Claude <noreply@anthropic.com>