docs for v0.206.0: CHANGELOG, CONTEXT, REUSE, README

CHANGELOG v0.206.0 with the ruling that reversed the fix, the three changes,
the SEC 7.2 staleness decision, Q7's closed trap, and the two bugs the tests
caught rather than review.

CONTEXT carries the three rules this session established, in the form the next
session needs them:
  - a box does not create a repository key while the hub holds a sealed
    package for it;
  - the fact that answers a question must be kept where the question is asked;
  - fix the state, do not remember that it is wrong.

REUSE gains four rows, each carrying the trap rather than just the signature:
the mint guard is a CONJUNCTION and t.Enabled is load-bearing in the derived
predicate; the discriminator ships INERT unless wired in main.go's confirmer
literal; the countdown removes BOTH halves or neither and must be driven by an
injected clock; and the epoch must be synced FIRST and unconditionally or the
falling edge is lost.

README documents the three customer-visible changes and the operator levers.

No version literal was edited: the controller version is ldflags-only.

REUSE.md

@@ -57,6 +57,10 @@
 
 | Symbol | File | Short signature | Use for | Gotchas |
 |---|---|---|---|---|
+| `backup.ErrOffboxSealedPackageHeld` + `IsOffboxSealedPackageHeld` + `sealedPackageHeld` + `OffboxAwaitingRecoveryKey` (R-241, v0.206.0) | controller/internal/backup/offbox.go | sentinel; `(error) bool`; `() bool`; `() bool` | **THE MINT GUARD** — a box never creates a repository key while the hub holds a sealed package for it | **The guard is a CONJUNCTION** (package held AND no key present). Widening it to "never mint" leaves a first-time box unable to start, waiting for a package that will never exist — pinned by `TestR241_ScenarioB_FirstTimeBoxStillMints`. **The refusal is a HOLDING state, not a failure:** `ApplyOffsiteTarget` catches the sentinel and still writes the transport, so `/recovery`'s synchronous tier-up (R-219) can bring the tier up the instant the key arrives; returning the error instead leaves `needsOffsiteCredential` true and the hub re-staging a consumed credential for ever. `OffboxAwaitingRecoveryKey` is **DERIVED, never stored** — and **`t.Enabled` is load-bearing in it**: a customer who switched off-site OFF is not awaiting anything (the Scenario-E carve-out `needsOffsiteCredential` makes two functions above; the first draft omitted it and an existing test caught it). A nil settings store reads as "no package held" — a transient read failure must never become a permanently-held tier |
+| `settings.HubEscrowKeySHA256` + `SetHubEscrowKeySHA256` / `GetHubEscrowKeySHA256`, and `OffsiteRecoveryOffer` **shape (c)** (R-241, v0.206.0) | controller/internal/settings/settings.go, controller/internal/backup/offbox.go | `(sha, checkedAt string) error` / `() (string, string)` | **THE DISCRIMINATOR the recovery screen asks** — does the hub hold a package for a key other than the one we use? | **The comparison was ALREADY computed on every ACK since SLICE 3 and persisted nowhere** — that is R-241's second half. Wire the recorder in `main.go`'s `EscrowAutoConfirmer` literal or shape (c) reads an empty hash for ever and the fix ships INERT (pinned by `TestMainWiresRecordEscrowKeyHash`). **§7.2 staleness, decided:** a KNOWN DIFFERENCE offers **however old the reading** — age is deliberately NOT gated on, because gating makes a box offline from the hub silently stop offering; an **ABSENT hash falls back to (a)/(b)** and does NOT offer, because `""` is the hub positively saying its package seals no key (legacy hash-less escrow), not an unknown. `CheckedAt` is for diagnosis, never a gate |
+| `backup.AbandonStatus` / `AbandonSweep` / `CancelAbandon` / `ClearAbandonPurgeIfConfirmed` / `ExtendAbandon` / `StopAbandon` + `AbandonGraceDays` (R-241, v0.206.0) | controller/internal/backup/offbox_abandon.go | see file | **The 14-day abandonment countdown** — the ONLY thing in the product that deletes a customer's off-site history | **BOTH HALVES OR NEITHER.** The set-aside store and the sealed package that protects it are two halves of one thing; removing only one leaves a package that opens nothing, or ciphertext nobody can decrypt. Not atomic across two machines, so it is a **two-phase commit**: delete the store, set `AbandonPurgeRequested`, and keep declaring it until the hub's ACK stops reporting a superseded package — the confirmation rides the SAME ACK as the request. **The countdown starts in `ResetOrphanedRepo`, NOT in the shared `resetOrphanedRepo`** — the helper is also the UNCLAIMED auto-reset, where nobody decided anything. **The recovery offer stays reachable for the whole grace** (a grace in which recovery is impossible is decorative). **Drive it with `SetOffboxClock`, never a shortened live timer** (§7.4). A transport failure leaves the countdown DUE so tomorrow retries; the operator levers REFUSE rather than no-op when nothing is running or the store is already gone |
+| `settings.SyncRecoveryOfferEpoch` / `PostponeRecoveryNoticeForEpoch` / `OptOutRecoveryRemindersForEpoch` + `web.recoveryBannerCookie` (R-241, v0.206.0) | controller/internal/settings/settings.go, controller/internal/web/recovery_handlers.go | `(offered bool, now) (RecoveryOfferView, error)` | **The offer EPOCH** — "once per entry into the offered state", not once ever | **Sync the epoch FIRST and UNCONDITIONALLY in `recoveryInterrupts`.** The first draft returned early when the offer was false, so the FALLING edge was never recorded, `RecoveryOfferActive` stayed true through a settled period, and the next entry counted as a continuation — **the exact defect the epoch exists to fix, reintroduced inside the fix**. Dismissals are recorded against the epoch they were made in, so a fresh entry resets them **by arithmetic**, with nothing to clear. **Three levers, three scopes, and NONE removes the entry point on `/backups/remote`:** the banner cookie is a browser SESSION cookie (no MaxAge — cleared on login) and persists nothing; the reminder opt-out is durable but silences the BANNER ONLY; "most nem" suppresses the full page only |
 | `atomicWrite` | controller/internal/backup/recovery_unit.go | `(path, data, perm) error` | Atomic file writes (backup pkg) | tmp+rename; no dir creation, no fallback |
 | `writeFileAtomic` | controller/internal/bootstrap/bootstrap.go | `(path, b) error` | controller.yaml writes from bootstrap | Always 0600 (holds local-api token + hub key) |
 | `writeConfig0600` | controller/internal/api/router.go | `(path, body) error` | config writes via API | ALWAYS chmods 0600 even pre-existing (F8); direct-write fallback on bind-mount EBUSY (non-atomic!) |