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/report/pusher.go

@@ -44,6 +44,10 @@ type PushResponse struct {
 	// pull-based ACK-flag pattern as escrow: the NEXT report ships the tails; the hub
 	// clears the pending request on receipt (consume-once). Absent/empty = nothing pending.
 	LogTailRequests []string `json:"log_tail_requests"`
+	// ControllerLogRequested (v0.116.0) — the operator wants THIS controller's own debug
+	// ring; the NEXT report ships controller_log_tail (selftail.go). Absent/false on an
+	// old hub = nothing pending.
+	ControllerLogRequested bool `json:"controller_log_requested"`
 }
 
 // Pusher sends reports to the central hub.