agent v0.25.0: slice 10 P2 — bind enrolled user-data drives into the guest

POST /disks/guest-attach binds an enrolled drive's felhom-data namespace into
the guest (Model A: felhom-data is the bind source mounted at /mnt/<name>, so
only Felhom's namespace crosses in). GuestBinder does mkdir+chown(100000)+pct set
(RW bind) via the fenced runner. Idempotent, free-slot selection, path-validated.
Spike-proven on 9201. Pairs with controller P2C + golden /mnt:rslave (P2B).

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

cmd/felhom-agent/main.go

@@ -43,7 +43,7 @@ import (
 
 // version is the agent version. Overridable at build time with
 // -ldflags "-X main.version=<v>"; defaults to the in-repo CHANGELOG version.
-var version = "0.24.0"
+var version = "0.25.0"
 
 func main() {
 	var (
@@ -554,6 +554,13 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 	}
 	logger.Info("local-api leaf ready", "fingerprint_sha256", fp, "cert", cfg.LocalAPI.CertPath())
 	runner := backup.NewBackupRunner(px, cfg.Backup.LocalBackupTarget, "", "felhom local-api", logger)
+	// Guest data-drive passthrough (slice 10 P2): a root-CLI runner for the `pct set` bind + chown
+	// (same fenced ExecRunner the host-storage + provision back-half use).
+	gaMode := proxmox.RunnerMode(cfg.Privileged.Mode)
+	if gaMode == "" {
+		gaMode = proxmox.RunnerSudo
+	}
+	guestBinder := localapi.NewGuestBinder(&proxmox.ExecRunner{Mode: gaMode, SudoPath: cfg.Privileged.SudoPath}, logger)
 	srv, err := localapi.NewServer(localapi.Options{
 		ListenAddr:    cfg.LocalAPI.ListenAddr,
 		Cert:          cert,
@@ -564,9 +571,11 @@ func buildLocalAPIServer(cfg config.Config, px *proxmox.Client, store *backup.St
 		Tokens:        tokens,
 		BackupCadence: cfg.Backup.BackupCadence(),
 		// Disk management (slice 8C): the privileged host surface + the data-bearing wipe gate.
-		Disks:    hostOps,
-		DiskGate: storageGateAdapter{gate: gate, hostID: cfg.Hub.HostID},
-		Guests2:  px,
+		Disks:       hostOps,
+		DiskGate:    storageGateAdapter{gate: gate, hostID: cfg.Hub.HostID},
+		Guests2:     px,
+		GuestAttach: guestBinder, // slice 10 P2: bind enrolled data drives into the guest
+
 		// Host metrics (slice 9): the shared collector serves GET /host/metrics — a fresh host +
 		// per-storage view to the customer's monitoring page (reuses the slice-4 collector).
 		HostMetrics: collector,