Status: OUT
Storage engines degrade monotonically during normal operation (leaked pages, growing height, no rebalancing) and have no safe recovery after crashes (non-atomic compaction, partial batch replay, unchecked metadata) — there is no path from degraded state back to healthy state.
depth-2 degradation + depth-2 crash unsafety combine to show no self-healing exists at any layer
Depends on (SL): btree-structural-integrity-silently-erodes, storage-crash-recovery-has-no-safe-path