During launch the live-status loop resumes every alive member every audit cycle.
resumeActiveIntervalsForMember runs a synchronous file-lock + full read of every
task file, so for an N-member team with M task files it did N locked passes x M
readFileSync per cycle (e.g. 6 members x 20 task files), blocking the main event
loop. Profiling a 6-member mixed launch showed mutateTeamTasks/withFileLockSync as
a top main-thread cost (~14%).
Add resumeActiveIntervalsForMembers that applies the identical per-member resume
logic against a member set in a single locked pass, and use it in the live-status
loop. Same mutations, but one lock + task read per cycle instead of one per member.
Adds a test covering multi-member resume in one pass.
