retention

name	retention
description	Change how old snapshots are pruned (age, count, size, pinned/labelled protection). Use when the library grows without bound or a named snapshot disappeared.

Retention

RetentionPlanner.plan is pure over [SnapshotSummary]. Preview in UI must use the same function the store executes.

• Newest snapshot is never deleted. Without it there is nothing to compare against.
• Default policy: 90 days, 1 GiB, protects pinned and labelled snapshots.
• Empty labels are not protection. protectsLabelled / protectsPinned can be turned off.
• Protected snapshots do not consume the count/size quota.
• Age is applied before count/size so the reason stays tooOld when both apply.
• SnapshotService.capture runs retention after save so the new snapshot always survives a tight limit.

Tests: Tests/Domain/RetentionPlannerTests.swift and retention invariants.