v0.116.0: observability pass — always-on debug ring + leveled sweep + agent tab + self-log pull — MinAgent: 0.81.0

Capture layer: LogBuffer always exists; logger = MultiWriter(LevelFilterWriter
(stdout, logging.level), ring) so DEBUG detail exists remotely without a config
flip while docker logs keep respecting the level. New internal/logx leveled
helpers. Report ACK gains controller_log_requested (additive); next report
ships controller_log_tail (128KB, consume-once, app-tail wire byte-compatible).
Debug page: Vezérlő|Ügynök tabs; agent tab proxies agent /debug/logs with the
pre-0.83 notice on typed 404. Sweep: netstorage_job phases, netprobe, handler
validation refusals + orphan WARN, SupportsWithSource gate line, agentapi
per-call DEBUG, migrate phase lines, tier2/offbox unswallowed persists.
Red-proofs: filter-disabled, drain-removed, dropped-phase-line all FAIL.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

controller/internal/backup/offbox.go

@@ -394,7 +394,10 @@ func (m *Manager) RunOffboxBackup(ctx context.Context) error {
 	t := m.settings.GetOffboxTarget()
 	base, env := m.offboxBaseArgs(t)
 	start := time.Now()
-	_ = m.settings.UpdateOffboxStatus(func(o *settings.OffboxTarget) { o.LastStatus = "running"; o.LastError = "" })
+	m.logger.Printf("[INFO] [offbox] backup run started (%d app(s) toggled)", len(apps))
+	if err := m.settings.UpdateOffboxStatus(func(o *settings.OffboxTarget) { o.LastStatus = "running"; o.LastError = "" }); err != nil {
+		m.logger.Printf("[WARN] [offbox] status persist (running) failed: %v", err)
+	}
 
 	var backedUp int
 	var missing []string
@@ -424,7 +427,7 @@ func (m *Manager) RunOffboxBackup(ctx context.Context) error {
 	if runErr == nil {
 		snapshots = m.offboxRecordStats(ctx, base, env)
 	}
-	_ = m.settings.UpdateOffboxStatus(func(o *settings.OffboxTarget) {
+	if perr := m.settings.UpdateOffboxStatus(func(o *settings.OffboxTarget) {
 		o.LastRun = time.Now().UTC().Format(time.RFC3339)
 		o.LastDuration = dur.Round(time.Second).String()
 		if runErr != nil {
@@ -446,7 +449,9 @@ func (m *Manager) RunOffboxBackup(ctx context.Context) error {
 			}
 			o.LastWarning = strings.Join(warns, " ")
 		}
-	})
+	}); perr != nil {
+		m.logger.Printf("[WARN] [offbox] status persist (final) failed: %v", perr)
+	}
 	if m.offboxNotify != nil {
 		m.offboxNotify(dur, snapshots, runErr)
 	}