R-444: weekly guest disk trim (pct fstrim) outside the night, under the heavy-op gate

Operator ruling 09 §3 decision 139. One exact sudoers rule FELHOM_FSTRIM
(`/usr/sbin/pct ^fstrim [0-9]+$`) + manifest entry guest-fstrim; new
internal/fstrim job: due Wednesday from 10:00 host-local, starts only
10:00-20:59, holds backup.InFlight (busy -> deferred to the next hourly
tick), failed trim retried at most 3x per week, bytes parsed from the
"(N bytes) trimmed" lines, last result per guest persisted in
<state_dir>/guest-disk-trim.json and reported as guest_disk_trim.
Config opt-out: "disk_trim": {"disable": true}.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

REUSE.md

@@ -160,6 +160,7 @@
 | `lanresolver.hostRoot` + `dnsmasqUnitPaths` (data seam, R-317) | internal/lanresolver/lanresolver.go | prod `hostRoot = "/"`; probe = the `dnsmasq` package's systemd UNIT, never `/usr/sbin/dnsmasq` (owned by `dnsmasq-base`) | internal/lanresolver/ensure_dnsmasq_test.go — fixture root tree + recording `proxmox.Runner`; the REAL `os.Stat` probe and `EnsureDnsmasq` run. `TestEnsureDnsmasq_ProductionProbeIsTheUnit` pins the production wiring |
 | `localapi.GuestAPI` / `BackupService` / `BackupStore` / `TokenAuthority` | internal/localapi/server.go | `*proxmox.Client`, `*backup.BackupRunner`, `*backup.Store`, `*TokenStore` | `fakeGuests`/`fakeBackups`/`fakeStore` internal/localapi/server_test.go |
 | `backup.InFlight` | internal/backup/inflight.go | `TryAcquire(what) (release, busy, ok)` / `Busy()` | THE host-wide "one heavy guest operation at a time" gate — shared by the local-API backup path and the restore-test scheduler (R-85) | A **LINK** guard, not a lock one: the scratch VMID never touches the live guest's vzdump lock, but an offsite restore PULLS multi-GB over the tunnel a backup PUSHES one. Callers **DEFER, never cancel** — a deferred restore-test costs coverage, a cancelled backup costs the backup. A nil gate is ungated (pre-R-85 callers). |
+| `fstrim.Trimmer` (R-444) | internal/fstrim/fstrim.go | `New(runner, guests, gate, statePath, logger)` / `Pass(ctx)` / `GuestDiskTrimStatus(ctx)` / `ParseTrimmed(out)` | the weekly `pct fstrim <vmid>` of owned running guests (Wednesday from 10:00 local, starts 10:00-20:59 only), under `backup.InFlight`; last result per guest persisted and reported as `guest_disk_trim` | A busy gate DEFERS to the next hourly tick, never waits; a failed trim retries at most `MaxAttemptsPerWeek`; the report reads the persisted record, it never runs pct |
 | `capability` store-grant probe (`storeGrantStatuses` / `storeGrantVerdict` / `Client.Permissions`) | cmd/felhom-agent/main.go, internal/proxmox/query.go | *"may the agent READ this backup tier?"*, one `capability.Status` per configured tier | R-185. **Never infer permission from an empty content listing** — `{"data":[]}` is what a FORBIDDEN tier and a NEWBORN tier both return, and that ambiguity hid an unreadable host tier on both demo boxes. Ask `/access/permissions` **as the agent's own token** (root always says yes). **The ungranted answer is not empty and not a 403** — it carries the privileges inherited from the box-wide `/` grant, so test for **`Datastore.AllocateSpace`** specifically; path-presence or `Datastore.Audit` reports a blinded storage healthy. Probed set comes from `BackupTiers()`, never a fixed list. Critical except the `local` fallback. Composes AROUND the sudo prober (the `poolReadStatus` precedent); `Status`'s wire shape is untouched so the hub alert is free. Unreachable PVE ⇒ degraded, never ok. |
 | `backup.RestoreTestState` | internal/backup/restoretest_state.go | `RecordSuccess(target,archive,tier,verified,t)` / `ProvenArchive(target)` / `ProvenRestoreTests(ctx)` / `LastSuccess(target)` / `OldestFirst(targets)` | Per-tier restore-test PROOF state, persisted (atomic tmp+rename) — **which archive** was proven, and when (R-86) | **Credit ONLY on success** — a permanently failing tier must keep sorting first, or it looks freshly proven and stops being retried. Ties break on target id: without it, two tiers proven in the same second rotate by Go's randomised map order. **This one NEEDS persistence unlike R-84** — R-84 had ground truth to consult (the archive is still on the storage); a restore-test destroys its scratch and leaves no artifact. **R-86: the ARCHIVE is the state, the time is metadata** — a time alone cannot answer "have we proven THIS archive", which is the due-check's whole question. A pre-R-86 file (bare RFC3339 per target) keeps its time and yields NO proven archive, so each tier is due once after the upgrade; reading a legacy time as proof of the current archive would invent a guarantee. **R-189: it is also the REPORTABLE half of the restore-test signal.** The in-memory `backup.Store` holds only this process's latest run, and under per-archive due-ness the agent will not re-test a proven archive — so a proof lost to a restart is not repeated for a whole archive generation (observed live: a passing 14.5 GB offsite restore reached no host-report). `ProvenRestoreTests` renders the stored proofs as `hub.RestoreTest` entries and the collector merges them; a record missing the archive or the tier is NOT emitted, because an unproven tier reading as proven is worse than the defect. **Only successes are stored, deliberately:** a success suppresses future work, a failure causes it. |
 | `hub.ProvenRestoreTestReporter` + `Collector.SetProvenRestoreTests` | internal/hub/collect.go | the DURABLE restore-test source, merged with the in-memory one | R-189. Merge rule: **one entry per tier, newest by `TestedAt` wins** — a fresh failure beats a stored success (the failure is the news, and it lives nowhere else), a stored success beats a stale in-memory entry after a restart, and a tier never appears twice (the hub would read two tests). An unparseable timestamp counts as OLDER, so a malformed entry cannot displace a good one. **The wiring is pinned by an AST test** — the method this replaced (`RestoreTestState.Snapshot`) carried a doc comment naming a host-report gauge and had no caller for weeks. |