Look twice before saying a probe failed, and say conditions in machine names (hq issue 277)

D2 raised a resolver urgent on one query that timed out while its machine was
loaded, and its summary carried the resolver's address and socket text, so the
operator channel withheld the whole alert.

- D2 asks every question up to three times, all at once; a resolver that
  answers nothing is held for the next run and raised urgent when two runs
  in a row find it silent. A wrong answer is still raised at once.
- Findings a single look can be wrong about carry Confirm: raised on the
  second look in a row, kept while open, never cleared-and-reraised. Used by
  D2 silence, D3 (also asks discovery twice), D6 behind, D9, D13 unmeasured,
  probe-failed of the doctor, and blind watchdog rows.
- Probe seat asks (D8, D13) are asked again when the bus brought no answer.
- Summaries name machines and say things in words; addresses, paths,
  domains and raw errors move to the evidence (D2, D5, D8, D9, D13, S12).
- internal/outward mirrors the messenger's content rule, allowing the mesh's
  machine names; the keeper rewords a summary that would be withheld and keeps
  it whole in the evidence; a TestMain lint fails the suite on any raised or
  linted finding that would be withheld.

cmd/mesh-controller/signals.go

@@ -527,7 +527,7 @@ func watchLease(f *signalFacts) []conditions.Observation {
 			Summary: "the controller serves WITHOUT the lease: nothing keeps a second controller from acting " +
 				"beside it, and its declarations carry no epoch. A bus whose user list is older than this " +
 				"controller does not grant it the lease's bucket: a push of the machine holding the bus sends " +
-				"the list that does, and the controller takes the lease within five seconds — " + l.unleased,
+				"the list that does, and the controller takes the lease within five seconds",
 			Said: l.unleased})
 	} else if l.held && !l.renewed.IsZero() && f.now.Sub(l.renewed) > leaseBound {
 		out = append(out, conditions.Observation{Scope: conditions.ScopeCore, ID: "controller.lease", Token: "late",
@@ -539,8 +539,9 @@ func watchLease(f *signalFacts) []conditions.Observation {
 	if !l.reset.IsZero() && f.now.Sub(l.reset) <= advisoryQuiet {
 		out = append(out, conditions.Observation{Scope: conditions.ScopeCore, ID: "controller.lease", Token: "reset",
 			Kind: "lease-lost", Machine: f.host, Severity: conditions.Urgent,
-			Summary: "the controller lease's bucket was raised again from nothing: " + l.resetSaid,
-			Said:    l.resetSaid})
+			Summary: "the controller lease's bucket was raised again from nothing: whatever held the lease before " +
+				"does not know it lost it",
+			Said: l.resetSaid})
 	}
 	var lost []string
 	newest := inventory.Epoch{}