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

REUSE.md

@@ -137,7 +137,9 @@
 | `timeAgoStr` | controller/internal/web/funcmap.go | `(s RFC3339 string) string` | Ago-format for STRING timestamps | Exists because `timeAgo(time.Time)` 500'd on strings (v0.93 bug) |
 | `Server.baseData` / `executeTemplate` | controller/internal/web/handlers.go + server.go | page-data plumbing | New pages | baseData injects nav/alerts/version; templates must pass `controller/scripts/template_id_gate.py` + `controller/scripts/emoji_gate.py` |
 | `Server.RequireAuth` / `CsrfProtect` / `csrfField` | controller/internal/web/auth.go + csrf.go | middleware | Any new authed route/form | csrfField emits the hidden input; setup wizard has its OWN csrf (§6) |
-| `LogBuffer` | controller/internal/web/logbuffer.go | ring buffer io.Writer | In-memory log capture for debug UI | — |
+| `LogBuffer` + `Lines(maxBytes)` | controller/internal/web/logbuffer.go | ring buffer io.Writer | In-memory log capture for the debug UI + the report `controller_log_tail` source | v0.116.0: ALWAYS constructed (any logging.level) — the logger is `MultiWriter(LevelFilterWriter(stdout, level), ring)`; `Lines` drops OLDEST to honor the byte budget |
+| `logx.Debugf/Infof/Warnf/Errorf` | controller/internal/logx/logx.go | `(l *log.Logger, format, args…)` | ALL NEW leveled log lines (the v0.116.0 sweep standard) | routing is the WRITER's job — Debugf always reaches the ring, stdout filters; nil logger = no-op; caller-attributed (Output calldepth 3) |
+| `web.LevelFilterWriter` | controller/internal/web/levelfilter.go | `NewLevelFilterWriter(w, minLevel)` | stdout leveling under the always-on ring | untagged lines parse INFO; always reports full length written |
 | `monitor.RunHealthCheck` / `EffectiveProtected` | controller/internal/monitor/healthcheck.go | system health report | Health + protected-container list | — |
 | `util.TruncateStr` | controller/internal/util/strings.go | `(s, maxLen) string` | Rune-safe truncation | The intended shared helper; stacks still uses its byte-based twin (§6) |
 
@@ -175,8 +177,10 @@
 |---|---|---|---|
 | `diskAgent` | controller/internal/web/storage_handlers.go | `*agentapi.Client` | `mockAgent` in controller/internal/web/storage_handlers_test.go |
 | `netAgent` + `Server.netAgentFn/netProbeFn/netListFn` | controller/internal/web/netstorage_job.go (+ server.go fields) | `*agentapi.Client` / `runNetProbe` (linux re-exec) / `agent.ListNetStorage` | `fakeNetAgent` + fn injections in controller/internal/web/netstorage_job_test.go — the NAS add orchestration never shells/TLS-dials in tests |
+| `Server.agentLogsFn` (func seam) | controller/internal/web/server.go | nil → `agentClient().DebugLogs` (agent GET /debug/logs) | injected in controller/internal/web/observability_test.go (incl. the pre-0.83 typed-404 notice path) |
+| `report.SetPendingControllerLog` / `SetControllerLogSource` | controller/internal/report/selftail.go | ACK-armed consume-once self-log pull (the logtail.go shape) | selftail_test.go; source = `logBuffer.Lines`, wired once in main.go |
 | `util.ParseVersion` / `util.Version.Compare` | controller/internal/util/version.go | THE one semver comparator (house rule: never a second) — selfupdate aliases it; agentapi's MinAgent comparison uses it | rejects pre-release/dev/latest (callers fall back, never trust); numeric compare (0.100 > 0.81) |
-| `agentapi.AgentVersionReporter` + `featureMinAgent` | controller/internal/agentapi/features.go | version-first Supports (v0.82.0 header channel); probe = fallback for header-less agents | a coupled feature adds BOTH a featureProbes row AND a featureMinAgent row |
+| `agentapi.AgentVersionReporter` + `featureMinAgent` | controller/internal/agentapi/features.go | version-first Supports (v0.82.0 header channel); probe = fallback for header-less agents | a coupled feature adds BOTH a featureProbes row AND a featureMinAgent row; v0.116.0: `SupportsWithSource` also reports HOW the verdict was reached (version/probe-cache/probe) for the gate log line |
 | `netProbeReadBack` (package var) | controller/internal/web/netprobe.go | `os.ReadFile` | overridden in TestNetProbeChild (nonce-tamper + cleanup-fail rows); package var because the child is a RE-EXEC'd process in production |
 | `quiesce.Backend` / `quiesce.Stacks` | controller/internal/quiesce/quiesce.go | adapter over `*agentapi.Client` / `*stacks.Manager` | `fakeBackend`/`fakeStacks` in controller/internal/quiesce/quiesce_test.go |
 | `channelhealth.Probe` (func) + `Sink` | controller/internal/channelhealth/checker.go | `Server.ProbeAgentChannel` / notifier adapter | `fakeSink` in controller/internal/channelhealth/checker_test.go |