v0.6.0-rc1: slice 6 Phase A — backup + the self-restore-test (local target)

The guest-level backup layer + the journaled self-restore-test (restore→boot→verify→
teardown) that closes "a backup you haven't restored isn't a backup". All benign
(reuses the slice-4 classifier/gate/journal; no new destructive class/crypto). Local
target only; PBS = Phase B. Restore to a NEW guest only. Backups crash-consistent.

- proxmox: DestroyLXC, VzdumpOptions.Notes (notes-template), LatestBackupVolID.
- reconcile: Engine.RunRestoreTest (journal Scratch entry BEFORE mutation; net link-down
  pre-boot; defer teardown always; benign gated destroy) + Recover extended to reap a
  leaked scratch guest (Scratch flag, special-cased before the UPID path; idempotent).
- internal/backup: runner (vzdump + archive resolve + bulk-gap = backup!=1) + cadence
  scheduler (4th daemon goroutine, default 24h) + in-memory report store.
- hub: Backup/RestoreTest filled; collector seams; cross-repo golden byte-identical +
  bidirectional key-set tests; hub handler logs a FAILED restore-test prominently.
- config BackupConfig (band 990000-990009 default); --selftest=backup / restore-test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -15,7 +15,7 @@
 - Module `gitea.dooplex.hu/admin/felhom-agent`; binary `felhom-agent` (`cmd/felhom-agent/`).
 - **Pure Go stdlib + `golang.org/x/crypto` only** — no web frameworks.
 - `go.mod` directive **go 1.25.0**; dep `golang.org/x/crypto v0.52.0` (declares go 1.25, will NOT build on Go 1.24). The **build server (192.168.0.180) runs go1.26.0** (upstream Go on PATH, backward-compatible). Build/run the agent there for live tests (same LAN as the demo host).
-- Version: `version` var in `cmd/felhom-agent/main.go`, overridable via `-ldflags "-X main.version=<v>"`; `--version` flag. **Current: v0.5.0** (slice 5 complete: storage observe/report + watchdog + the host-root surface — mounts/SMART/grow/destructive gate). Bump on meaningful changes + add a CHANGELOG entry.
+- Version: `version` var in `cmd/felhom-agent/main.go`, overridable via `-ldflags "-X main.version=<v>"`; `--version` flag. **Current: v0.6.0-rc1** (slice 6 Phase A: backup + the self-restore-test, local target; PBS = Phase B). Bump on meaningful changes + add a CHANGELOG entry.
 
 ## Layout
 
@@ -26,8 +26,9 @@ internal/log/        slog setup
 internal/proxmox/    API-first Client + fenced root-CLI Privileged + UPID WaitTask
 internal/authz/      operator signed-op verifier (SSHSIG); durable FileNonceStore
 internal/hub/        daemon: HostReport collector + Bearer client + resilient Loop
-internal/reconcile/  reconcile engine + reversibility gate + op journal + crash recovery
+internal/reconcile/  reconcile engine + reversibility gate + op journal + crash recovery + restore-test
 internal/storage/    storage-target observer + durable_id + fast-poll watchdog (slice 5)
+internal/backup/     vzdump backup runner + restore-test scheduler + report store (slice 6)
 ```
 
 ## Proxmox model (the load-bearing rules)
@@ -54,7 +55,8 @@ Built in slices, all on `main`:
 - **v0.4.0** — slice-4 **Phase B** (security core): the benign/destructive **classifier** (provenance + data-bearing, not by verb; scratch/same-txn provenance is agent-internal, never hub-sourced), the **reversibility gate** (destructive → `pending_signature` unless a verified, role-scoped, action-bound operator signature), the **signed-op consuming layer** over `internal/authz` (role-scoping per doc 04 §4, op-to-action binding, idempotency-by-nonce, audit), and the **crash-recovery consumer** (`Recover` over `InFlight()`, resume-or-rollback). The gate fronts the queue's executor (every mutation passes it). **Inert this slice** — no destructive deltas served until slice 10; the destructive path is classified, gated, and adversarially tested but not wired to live execution. `authz` surface untouched.
 - **v0.5.0-rc1** — slice-5 **Phase A** (read-only, live): `internal/storage` — the `StorageTarget` wire contract (filled the slice-3 stub), `durable_id` derivation per type, the `Observer`, and the **storage watchdog** (third daemon goroutine; fast-poll → debounced out-of-band report on a known target's attach/disconnect). Hub ingest accepts/persists `storage_targets`; cross-repo golden byte-identical.
 - **v0.5.0** — slice-5 **Phase B** (the host-root surface): the `HostOps` seam + `SudoHostOps` (systemd `.mount` units by fs-UUID, detach, SMART, lvs) behind a **strict argument validator** (the adversarial matrix is the headline security test — hostile UUID/path/device refused with zero exec); SMART (SATA+NVMe) + thin-pool metadata enrichment; the watchdog's benign **re-mount response** (off the poll path); the **disk-grow executor** (`pct resize`, grow-only, benign) and **destructive storage ops** through the slice-4 gate (target-scoped; built + tested, inert live); `--selftest=storage [-watch]`; `configs/felhom-agent.sudoers`.
-- **Next: slice 6 (backup/restore orchestration)** — vzdump/PBS + the self-restore-test; the restore-overwrite executor the gate already guards.
+- **v0.6.0-rc1** — slice-6 **Phase A** (backup + self-restore-test, local target): proxmox `DestroyLXC`/`Vzdump`-notes/`LatestBackupVolID`; `Engine.RunRestoreTest` (journaled scratch lifecycle: restore-to-new → net link-down → boot → verify running → defer teardown, all benign); `Recover` extended to reap a leaked scratch guest (Scratch journal flag, special-cased before the UPID path); `internal/backup` (runner + bulk-gap + cadence scheduler + report store); hub `Backup`/`RestoreTest` filled (cross-repo golden + hub logs a failed restore-test); `--selftest=backup`/`--selftest=restore-test`. Live-validated on demo-felhom.
+- **Next: slice 6 Phase B (PBS)** — datastore on the USB, zero-knowledge key custody, restore-from-PBS, PBS integrity-verify (the lighter frequent check). Then slice 7 (provisioning + identity-reset + golden base, §9).
 
 ## Demo host (for live tests)