Keep serving the consumers postgres's grant file gives on its moved path (issue 937)

Only a moved consumer's plan names postgres, so on the moved path every
consumer still given by the controller's grant file was counted unasked
and offered for retirement (ace 5 of 5, novox 7 of 9), and could have
been retired unasked where the bound allowed. The moved path now reads
MESH_RECEIVES again: its logins are asked, the ones no plan names are
made and checked by the harness's grant pass until R1 (issue 682), and
an unreadable grant file retires nothing (issue 241). The harness's
grant pass becomes apply, identically in keycloak's copy.

modules/postgres/cmd/postgres-provider/harness.go

@@ -321,6 +321,29 @@ func (h *Harness) Reconcile(ctx context.Context) {
 		want[g.As] = true
 	}
 	h.seed(ctx, want)
+	h.apply(ctx, given)
+
+	// Retire what the mesh has stably stopped asking for — within the bound, or with a person.
+	h.retireUnasked(ctx, want)
+	h.r.lastWant = want
+	for as := range h.failing {
+		if !want[as] {
+			delete(h.failing, as)
+		}
+	}
+	// A consumer the mesh stopped asking for that this provider holds nothing for is no longer failed by
+	// anyone: said, so a standing the controller keeps for it is cleared rather than left naming a
+	// consumer that is gone. One still held is said recovered when it is retired.
+	for as := range h.trouble {
+		if _, held := h.applied[as]; !want[as] && !held {
+			h.recovered(as, "no longer asked for")
+		}
+	}
+}
+
+// apply makes each consumer the grant file gives, and checks every VerifyEvery that the backend still holds it. The
+// caller holds h.mu. One consumer's failure never stops the others'.
+func (h *Harness) apply(ctx context.Context, given []contribution) {
 	verifying := h.Now().Sub(h.verifiedAt) >= h.VerifyEvery
 	if verifying {
 		h.verifiedAt = h.Now()
@@ -423,23 +446,6 @@ func (h *Harness) Reconcile(ctx context.Context) {
 			}
 		}
 	}
-
-	// Retire what the mesh has stably stopped asking for — within the bound, or with a person.
-	h.retireUnasked(ctx, want)
-	h.r.lastWant = want
-	for as := range h.failing {
-		if !want[as] {
-			delete(h.failing, as)
-		}
-	}
-	// A consumer the mesh stopped asking for that this provider holds nothing for is no longer failed by
-	// anyone: said, so a standing the controller keeps for it is cleared rather than left naming a
-	// consumer that is gone. One still held is said recovered when it is retired.
-	for as := range h.trouble {
-		if _, held := h.applied[as]; !want[as] && !held {
-			h.recovered(as, "no longer asked for")
-		}
-	}
 }
 
 // failed counts one more failure in a consumer's unbroken run, and announces the run once it has