v0.204.0 — the restore list is keyed on the store (R-237); the size gate stops refusing in silence (R-238)

R-237: /backups/restore listed apps that are CURRENTLY DEPLOYED and CURRENTLY
TOGGLED ON for future off-site backups. A rebuilt box has neither, so a household
that had just lost everything was shown nothing to restore while the repository
held their snapshots — measured live on the R-201 re-walk. To restore an app you
had to select it, to select it you had to have installed it, and to know what to
install you had to see the backup you could not see.

The store is now the source of the list (offsite_restore_list.go), built on the
existing R-193 OffsiteInventoryList. Installed-ness became a property OF a row,
never a filter on it. Every case is answered rather than hidden: a snapshot for an
app that is not installed is offered and says it will reinstall first; an installed
app with no snapshot is shown as having nothing; an unreadable store renders as
UNKNOWN (R-225's rule, one screen over) AND keeps the action, because "we could
not look" is not "there is nothing"; no-target is its own state. The felhom-offbox
and _shares marker tags are excluded from the app list.

R-238 classified as a HARNESS ARTIFACT: mode=full without confirm=1 is step 1 of a
deliberate two-step — it starts no job by design and redirects carrying
&full_prep=<app>, which deriveWizardStep requires to reveal the commit. A driver
that did not carry it forward landed back on the intent step. The operator's
browser run completed the same restore. The wizard's precedence rules were NOT
re-keyed: a stale ?full_prep= must never resurrect a commit button mid-restore.

The residue WAS real and is fixed: neither branch of that step wrote anything to
the log, so a refusal — including by the headroom gate — left no trace on the box.
Both branches now log, and so does the concurrent-op refusal.

resolveWizardApp is removed: it was dead once the gate moved, and its test pinned
the defect's behaviour (an untoggled app refused), which would have read as policy.

28 packages ok, 9/9 gates OK. Three red-proofs, each asserted to have applied.

controller/internal/backup/offbox_inventory.go

@@ -29,6 +29,12 @@ var errNoOffsiteTarget = errors.New("no off-site target is configured on this bo
 // thing rather than showing a generic failure.
 func ErrNoOffsiteTarget(err error) bool { return errors.Is(err, errNoOffsiteTarget) }
 
+// ErrNoOffsiteTargetSentinel exposes the sentinel itself so other packages — and their tests — can
+// construct the not-yet-configured case. Added for R-237, whose restore list must distinguish
+// "no target yet" (resolves by itself) from "could not read" (does not), and must be able to pin
+// both in a table test.
+func ErrNoOffsiteTargetSentinel() error { return errNoOffsiteTarget }
+
 // OffsiteInventoryApp is one app's presence in the opened repository. Non-secret throughout.
 type OffsiteInventoryApp struct {
 	App       string    // the restic tag == the stack name