docs: v0.242.0 report, context; R-489 measured limit recorded (row kept open)

A volume recreated by a unit restore carries no compose label, so the
before/after difference misses it; proven on the scratch guest. Docs only,
no release.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

CONTEXT.md

@@ -7,7 +7,17 @@
 >
 > Ask Claude Code: "Please update CONTEXT.md with what we did today"
 
-Last updated: 2026-09-13 (v0.237.0 — update arc slice 4: the guarded update)
+Last updated: 2026-09-13 night (v0.242.0 — R-487 removed-app listing + R-491/R-490/R-489/R-476/R-456)
+
+> **2026-09-13 night — v0.242.0 (R-487 / R-491 / R-490 / R-489 / R-476 / R-456).** The local backup
+> lists are keyed on the DRIVES, not on what is deployed (`ListRemovedAppUnits`, the R-237 rule one
+> tier down): a removed app whose unit was kept is listed with its restore, the picker and
+> `/api/backup/snapshots` answer for it, and the restore opens the unit where it sits
+> (`primaryUnitDirFor`). A removal clears an update hold. `/api/system/info` reaches the API router.
+> `volumes_removed` is a before/after difference — **but a volume recreated by a unit restore has no
+> compose label and is missed (R-489 open, residual: list by `<project>_` prefix too)**. Tier-2 copy
+> date = newest dump (`UnitDataDate`) unless the leg was preserved. **The scratch guest 9202 on demo-hp
+> is where releases are validated now** (hand-set image; hub/tunnel off) — `felhom.eu/CONTEXT.md`.
 
 > **2026-09-13 — v0.237.0 (slice 4: R-448, R-443, R-439).** Update is a guarded 202 job:
 > refusals (hold, busy, memory, disk, no restorable Tier-2 copy) → backup-first if the proven copy is