Add snapshot participant counts

[JackWilb]

Summary

• add Completed, In Progress, and Rejected columns to the Manage Data snapshots table
• store participant status counts on new snapshot metadata and preserve them on rename
• lazily backfill counts for existing snapshots and keep actions usable if backfill fails

Tests

• yarn unittest src/analysis/individualStudy/management/tests/ManageView.spec.tsx --run
• yarn unittest src/storage/tests/primitives.spec.ts --run
• yarn typecheck
• yarn lint

Closes #1184

[github-actions]

🪓 PR closed, deleted preview.

[jaykim1213]

Resolved
In DataManagementItem.tsx, const strippedFilename is used in fetchParticipants and backfill useEffect. Can we make this into a helpfer function like:

function getSnapshotStudyId(snapshotKey: string) {
  return snapshotKey.slice(snapshotKey.indexOf('-') + 1);
}

[jaykim1213]

Resolved
This might be a separate issue, but the snapshot list is not sorted by creation date. Can we sort snapshots by date?

[JackWilb]

Addressed all review feedback in commit 5cf28547:

• Added shared helper getSnapshotStudyId(snapshotKey) and reused it in both the lazy backfill path and snapshot download participant fetch path.
• Sorted snapshot rows by creation timestamp, newest first, using the timestamp embedded in the snapshot key. Added a unit test for the ordering.
• Updated failed backfills to remove the snapshot key from snapshotCountBackfills.current, so a later render or refresh can retry instead of leaving it permanently marked in-flight.
• Changed getAllParticipantIds to prefer an explicit studyId argument with studyId ?? this.studyId, which is important when fetching participants for snapshot study IDs instead of the currently initialized live study.

Checks run:

• yarn unittest src/analysis/individualStudy/management/tests/ManageView.spec.tsx --run
• yarn unittest src/storage/tests/primitives.spec.ts --run
• yarn typecheck
• yarn lint

[jaykim1213]

Looks great thank you!