A merge produces a tiered plan the mesh keeps (hq ADR 0162)

A module's dependencies are one relation in the catalogue — stands-on, packages, built-by, declared —
answered by one call. A merge takes what moved and everything reachable from it, sorts the set into
tiers (a code dependency in the same tier, a build dependency after its base is built, a runtime
dependency after the build machine is built and running; the build machine's own base comes first,
built by the one that runs), writes the plan to the store, asks the first tier and returns. Every
outcome advances the plan; a ticker advances what outcomes cannot; a controller replaced mid-plan
resumes it. status lists open plans and names one that has waited too long.

cmd/mesh-controller/push.go

@@ -114,6 +114,9 @@ func serve(ctx context.Context) error {
 	// And build results nobody was waiting for. A build triggered any other way than `build`
 	// would otherwise be reported into the void, which is the same as not reporting it.
 	server.Records(builds{inv})
+	// Open plans move on a timer as well as on outcomes (novox/hq ADR 0162): a tier waiting for
+	// machines to report moves when they have, and a plan left by a replaced controller resumes.
+	go planTicker(ctx, inv)
 	// And what the catalogue decided a build meant. The builder's own result is already handled
 	// above; this is the other half — the control plane is the only one of the three that knows
 	// which machines run the thing, so it is the one that acts (novox/hq ADR 0072).