The catalogue asks on start, and registers a replay as history

A replayed build is registered exactly as any other and announced to nobody. A
module that moved months ago is not something anything should act on now:
emitting `upgraded` would have the control plane decide about a rollout, and
`rebuild-needed` would ask for builds of things already current.

Asked on every start rather than only the first, because a catalogue cannot tell
whether it has a gap — and the answer is idempotent, so asking when there is none
costs a message. Asked after subscribing, so a build arriving during the replay
is not lost between the two.

Closes novox/hq 04-ISSUES/050 with mesh-control.

Claude-Session: https://claude.ai/code/session_01D6qtiYU3P9jk3pnAXyAFyx

modules/mesh-catalog/index.ts

@@ -36,6 +36,15 @@ interface Built {
    * produced it. Turning that into an edge between module-versions is this module's job.
    */
   against?: string[];
+  /**
+   * This is history, not news — the mesh re-announcing a build this catalogue was not there for.
+   *
+   * Registered exactly as any other, and announced as nothing. A module that moved months ago is
+   * not something anything should act on now: emitting `upgraded` would have the control plane
+   * decide about a rollout, and `rebuild-needed` would ask for builds of things that are already
+   * current.
+   */
+  replay?: boolean;
 }
 
 await on("module.builder.built", async (event) => {
@@ -56,6 +65,10 @@ await on("module.builder.built", async (event) => {
     manifest: body.manifest ?? {},
   }, body.made ?? [], body.against ?? []);
 
+  // **A replay is registered and announced to nobody.** See `replay` above: the graph gains what
+  // it was missing, and the mesh is told nothing happened, because nothing did.
+  if (body.replay) return;
+
   await emit("module.mesh-catalog.registered", {
     module: body.module, commit: body.commit, upgraded,
   });
@@ -77,3 +90,15 @@ await on("module.builder.built", async (event) => {
     });
   }
 });
+
+// **And ask for what was built before this catalogue existed** (novox/hq 04-ISSUES/050).
+//
+// The queue above is durable, so nothing is missed once this is running. What it cannot have is
+// what was announced before it first ran — and on a fresh mesh that is never arbitrary: the shared
+// base, the store this runs on, and this module itself are each necessarily built BEFORE a
+// catalogue exists to hear about them. The graph's foundation is the part it never sees.
+//
+// Asked on every start, not only the first. A catalogue cannot tell whether it has a gap, and the
+// answer is idempotent: registering a build already held changes nothing and announces nothing.
+// Asked AFTER subscribing, so a build arriving during the replay is not lost between the two.
+await emit("module.mesh-catalog.catching-up", {});