fix(pbs): Verify forces ignore-verified=false; restore-test source_tier from storage type

Live PBS runbook surfaced two gaps: (1) PBS verify defaults to ignore-verified=true and
SKIPS already-verified snapshots, so corruption after the first verify is never caught —
the agent's integrity check now POSTs ignore-verified=false to actually re-read+re-check.
(2) restore-test source_tier was hardcoded 'local'; now derived from the source storage
type ('pbs' for a PBS datastore). Adds a form-POST path to the PBS client.

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

cmd/felhom-agent/main.go

@@ -346,6 +346,21 @@ func pbsTargetsFromPVE(cfg config.Config, px *proxmox.Client, logger *slog.Logge
 	}
 }
 
+// storageTier returns the restore-test source tier for a backup storage id: "pbs" when that
+// storage is a PBS datastore, else "local". Best-effort (a lookup failure → "local").
+func storageTier(ctx context.Context, px *proxmox.Client, storageID string) string {
+	stores, err := px.ListStorage(ctx)
+	if err != nil {
+		return "local"
+	}
+	for _, s := range stores {
+		if s.Storage == storageID && s.Type == "pbs" {
+			return "pbs"
+		}
+	}
+	return "local"
+}
+
 // readTrimmed reads a file and trims surrounding whitespace/newline (for the .pw secret).
 func readTrimmed(path string) (string, error) {
 	b, err := os.ReadFile(path)
@@ -381,7 +396,7 @@ func buildRestoreTestScheduler(cfg config.Config, px *proxmox.Client, engine *re
 			RestoreStorage: cfg.Backup.RestoreStorage,
 			ScratchMin:     min,
 			ScratchMax:     max,
-			SourceTier:     "local",
+			SourceTier:     storageTier(context.Background(), px, cfg.Backup.LocalBackupTarget),
 		},
 		Cadence: cadence,
 		Logger:  logger,
@@ -665,7 +680,7 @@ func runSelftestRestoreTest(ctx context.Context, cfg config.Config, logger *slog
 	fmt.Printf("  restoring %s into scratch band [%d,%d] on %s …\n", archive, min, max, cfg.Backup.RestoreStorage)
 	res := engine.RunRestoreTest(ctx, reconcile.RestoreTestSpec{
 		Archive: archive, RestoreStorage: cfg.Backup.RestoreStorage,
-		ScratchMin: min, ScratchMax: max, SourceTier: "local",
+		ScratchMin: min, ScratchMax: max, SourceTier: storageTier(ctx, px, cfg.Backup.LocalBackupTarget),
 	})
 	printJSON("restore-test record", backup.ToHubRestoreTest(res, time.Now().UTC()))
 	if res.Skipped {