Keep each walk's phases and say a delivery over its budget (hq ADR 0282 slice 1, issue 382)

The operator's budget (a leaf module running everywhere within five minutes
of its merge, a core module within ten) cannot be held to without knowing
where a walk's time goes. A walk now keeps when its batch's window closed,
when it was cut and its class (migration 0093), each gate reading, and what
each machine of the rest was sent; 'delivery walks' and plan-moved say its
phases from the merge to every machine of the rest reporting the build
applied, and ended walks keep them as walk-phase durations per class. Probe
D16 reads mesh-delivery's 'times' and raises delivery.<class>.over-budget.
A phase that cannot be measured is said unknown, never zero. Measurement
only: no walk is held, sent or judged differently.

cmd/mesh-controller/gate.go

@@ -603,6 +603,7 @@ func judgeMoves(ctx context.Context, open *stores, g *inventory.PlanGate, pairs
 	pastBound := now.Sub(*g.Since) > gateBound
 	switch {
 	case worst == healthBroken:
+		g.Read(now, false, g.BrokenWhy)
 		var judging []string
 		for _, m := range modules {
 			if reading[m] != healthBroken && !passedAlone(m) {
@@ -621,8 +622,10 @@ func judgeMoves(ctx context.Context, open *stores, g *inventory.PlanGate, pairs
 		// Waiting on a provider that is unhealthy: not a pass, and not a failure at the bound either —
 		// the provider's own condition says what is wrong (ADR 0240 rule 5).
 		g.Passes, g.LastPass, g.Last, g.Failing = 0, nil, why, failing
+		g.Read(now, false, why)
 	case worst == healthNotYet:
 		g.Passes, g.LastPass, g.Last, g.Failing = 0, nil, why, failing
+		g.Read(now, false, why)
 		if pastBound {
 			fail(fmt.Sprintf("not healthy within %s of its apply: %s", gateBound, why))
 		}
@@ -630,6 +633,7 @@ func judgeMoves(ctx context.Context, open *stores, g *inventory.PlanGate, pairs
 		// Healthy, or waiting for a person (ADR 0254): a pass, the wait carried along in the verdict.
 		g.Passes++
 		g.LastPass, g.Last, g.Failing = &now, "", nil
+		g.Read(now, true, "")
 		if g.Passes >= gatePasses && settled {
 			decide(g, inventory.GatePassed, fmt.Sprintf("healthy %d times over %s", g.Passes,
 				now.Sub(*g.Since).Round(time.Second))+waitsSaid(g.Waits), now)