v0.122.0: three ways the signals lied about themselves (R-189, R-188, R-186)

All three are the reporting and release path misreporting its own work. No
customer machine, no backup, no restore, no data. The restore-test itself and
when it runs are unchanged.

R-189 — a passing restore-test no longer vanishes on a restart. restore_tests[]
came only from the in-memory store, whose comment ("lost on restart; the cadence
re-populates") was true under a timer and stopped being true when R-86 made the
agent refuse to re-test a proven archive: the proof is then not repeated for a
whole archive generation. Observed live — a 14.5 GB offsite PASS reached no
host-report because the agent was restarted 2m43s later. RestoreTestState now
carries tier + verified beside the archive and renders reportable entries; the
collector merges them, one per tier, newest by TestedAt. It refuses to lie: a
record missing archive-or-tier produces no entry, and run mechanics are not
re-invented. Only successes are persisted, and the asymmetry is now written where
it will be read.

R-188 — a correct release stops emailing a failure. Only the tag PUSH moved
(build -> tag locally -> publish -> push tag): the push wakes CI, and a tag
visible before its package made the gate correctly fail a correct release about
half the time. The old order's invariant is asserted directly instead — the gate
now refuses a published version with no tag, as a bounded probe that prints its
own coverage, because the package listing api is still 401 without a token.

R-186 — a released binary can be verified by rebuilding it. -trimpath
-buildvcs=false: same source, same bytes, tag or no tag. Measured. publish-agent's
fallback also forced CGO_ENABLED=0 and produced a 74 KB different binary for the
same version; both paths now build identically. CLAUDE.md records the command.

internal/backup/store.go

@@ -10,8 +10,22 @@ import (
 // Store holds the agent's LATEST backup result per target and the latest restore-test
 // result — the point-in-time state the host-report surfaces. It is updated by the backup
 // runner + the restore-test scheduler/selftest and read by the collector via the hub
-// BackupReporter / RestoreTestReporter seams. In-memory (lost on restart; the cadence
-// re-populates) and mutex-guarded for the concurrent collector vs scheduler access.
+// BackupReporter / RestoreTestReporter seams. In-memory and mutex-guarded for the concurrent
+// collector vs scheduler access.
+//
+// **"lost on restart; the cadence re-populates" — that sentence used to be here and it is now
+// FALSE for restore-tests (R-189, 2026-08-03).** It was true while a timer re-tested every tier
+// daily. Under R-86's per-archive due-check the agent will NOT re-test an archive it has already
+// proven, so a proof lost to a restart is not repeated until the next archive generation — a week on
+// the offsite tier — and the hub reports that tier unproven throughout. Observed, not predicted: a
+// real 14.5 GB offsite restore passed, the agent was restarted 2 m 43 s later for a deploy, and two
+// consecutive host-reports carried `0 restore-tests`.
+//
+// The durable half is `RestoreTestState` (on disk, per tier, with the archive) and the collector
+// merges the two — see hub.ProvenRestoreTestReporter. This store remains the ONLY place a FAILURE is
+// recorded, and that asymmetry is deliberate: a failing tier stays due and is retried, so a lost
+// failure heals itself, while a lost success leaves the system quietly less tested than it believes.
+// Backups are unaffected — their freshness has a ground truth on the storage (R-84).
 type Store struct {
 	mu       sync.Mutex
 	byTarget map[string]hub.Backup // latest backup per target id