Say when the mesh is wrong: conditions, watchdogs, the bus's advisories, doctor (hq to-be 45 Phase 1)

Every one of the 48 core failures of research 031 was found by a person
looking; the mesh's answers carried the fact for whoever asked and told
nobody.

- The condition store (to-be 45 §2): mesh-controller_conditions, one key
  per open condition, written by compare-and-set so a person's silence
  and the watchdogs never lose each other's word; every transition kept
  ninety days in mesh-controller_condition-history and said as the
  seat's events condition-raised / condition-changed / condition-cleared
  (the condition at the top level, with event, at, change, why, show),
  offered again while the bus is away. Raised and cleared by observation
  only; a clearing reopened within ten minutes is the same condition with
  its count up, its silence kept. Verbs: conditions, conditions show,
  conditions silence (a hand act, at most a week), conditions history.
- ADR 0224's provider standing is the first kind, provider-failing, held
  by the provider's events; the provider_standing table is no longer read
  or written (left in place: dropping it is the operator's word).
- status leads with the open conditions, urgent first, and says all well
  only with none open; conditions it cannot read are said and not well.
- The signals table compiled in, one watchdog loop over it every 30s: S1
  heartbeat (3 intervals, asleep machines excepted, control node urgent
  after 30 min), S2 report after a send, S3 plan tier, S4 event loop deaf,
  S5 merge not acted, S6 ask lost, S7 call hung, S8 provider silent, S9
  advisories, S10 self-check silent, S11 node tools silent, S13 stale
  refusals; S12, S14, S15 deferred with their reasons. A row that cannot
  see raises probe-failed and clears nothing. A test generated from the
  table suppresses each signal inside and past its bound.
- The bus's advisories (maximum deliveries, a mesh consumer deleted) and
  the controller's own slow consumer and refused subjects, said in the
  mesh's words.
- doctor: the probe registry D1-D10 (D5 deferred) and DW, every five
  minutes, each in thirty seconds; a probe that cannot run is never a
  pass. D1 validates with mesh-host's own validator. Every run ends with
  the doctor-heartbeat event mesh-watcher listens for.
- The controller is granted its new buckets, events, the two advisories
  and $SRV.INFO; the node tools their tools-alive heartbeat. The streams
  and consumers the controller asserts and the ones D6/D7 expect are one
  derivation.

internal/link/bus.go

@@ -71,6 +71,10 @@ const (
 	// next heartbeat, and a stream of them is the mesh's least valuable message competing for
 	// retention with its most valuable (design 25 §3).
 	AliveSubjects = "mesh.control.*.alive"
+
+	// ToolsAliveSubjects is every machine's node tools saying they are there (novox/hq to-be 45 §3,
+	// S11): core NATS like the host's, for the same reason.
+	ToolsAliveSubjects = "mesh.control.*.tools-alive"
 )
 
 // ReportSubject is where one node says what it did. On the CONTROL stream, because it is the
@@ -80,6 +84,9 @@ func ReportSubject(node string) string { return "mesh.control." + node + ".repor
 // AliveSubject is one node's heartbeat.
 func AliveSubject(node string) string { return "mesh.control." + node + ".alive" }
 
+// ToolsAliveSubject is one machine's node tools' heartbeat.
+func ToolsAliveSubject(node string) string { return "mesh.control." + node + ".tools-alive" }
+
 // EventSubject is where a module's event lands. Derived from the emitter, never taken from the
 // caller: a source that could differ from the subject is an envelope that can lie about its
 // origin, and on NATS the account's permissions make the subject the authority (design 29 §2).