testing: bootstrap UI, agent reliability, NS-01..04 + alert username

Smoothes the rough edges that came up exercising a live deployment.

First-run bootstrap UI: /bootstrap renders a username + password form
that uses the in-memory token directly (operator no longer copies it
out of the log); /login redirects there while bootstrap is available.

Agent reliability: failJob synthetic envelopes so command.run early
returns no longer hang the server-side job; runtime probe of restic
restore --help drives --no-ownership instead of version sniffing
(0.18.x had it removed). Server unit re-shaped: ProtectSystem=full
plus ReadWritePaths=/etc/restic-manager, no ProtectHome — restore
can now write anywhere a user might want.

Restore wizard: default target is /root/rm-restore/<job-id>/ with
clearer help text. Re-init confirm input uses .field (was .input,
which doesn't exist — text was invisible).

NS-01 host delete: store DeleteHost, admin-band /hosts/{id}/delete
with hostname-confirm danger zone, audit, FK cascade, live WS close.

NS-02 enrollment-token recovery: outstanding-tokens panel on
/hosts/new, regenerate (preserves attachments) and revoke handlers
+ audit, store-level ListOutstandingEnrollmentTokens and
DeleteEnrollmentToken.

NS-03 repo init / probe surface: migration 0020 adds
hosts.repo_status + repo_status_error; WS handler projects every
init job's outcome onto the host row (idempotent already-initialised
collapses to ready); creds-save resets status and dispatches a fresh
probe; /hosts/{id}/repo/probe retry endpoint with banner.

NS-04 dashboard live + sort + filter: query-string filter
(q/status/repo_status/tag/sort/dir), 5s htmx live poll mirroring the
alerts pattern with a localStorage live toggle, sortable column
headers, filter row + clear.

Alerts page: ack'd-by line resolves user_id ULID to username.

Compose.yaml ignored — host-specific.

internal/server/http/ui_restore.go

@@ -391,13 +391,15 @@ func (s *Server) handleUIRestoreTree(w stdhttp.ResponseWriter, r *stdhttp.Reques
 
 // defaultRestoreTargetDir is the placeholder shown on the step-3
 // New-directory radio card and the value used when the operator
-// leaves the field blank. $HOME resolves agent-side (typically /root
-// for the systemd-as-root unit); <job-id> is substituted at dispatch.
-// The systemd unit pins ReadWritePaths to include the agent user's
-// home/rm-restore subdir so this default actually works under the
-// sandbox.
+// leaves the field blank. The agent runs as root under systemd, so
+// we surface /root explicitly rather than $HOME — operators were
+// confused by "agent user's home" copy when the underlying user is
+// always root anyway. <job-id> is substituted at dispatch. The unit
+// no longer pins ReadWritePaths (ProtectSystem=full + no ProtectHome),
+// so operators can point this at /home/<user>/<wherever> directly
+// when they want a specific destination.
 func defaultRestoreTargetDir() string {
-	return "$HOME/rm-restore/<job-id>/"
+	return "/root/rm-restore/<job-id>/"
 }
 
 // looksLikeRestoreTarget validates the operator-supplied target dir