events: modules log activity to the broker, any module reacts

The lighter sibling of provisioning — 1:many and broadcast, no credential,
just the broker's topic routing. A thin, audit-ready surface over the
broker's publish/subscribe:

- emit(type, body): publishes an Event carrying who emitted it (MESH_MODULE),
  on which node (MESH_NODE) and when (ISO timestamp) — so a listener can
  build a real audit trail.
- on(pattern, handler): react to events by topic pattern. The audit logger
  is just on("#", ...).

Tested: a module emits; a targeted listener (module.umami.#) hears only its
events, the audit sink (#) hears every module's, and the metadata audit
needs is present.

The declared side — a manifest's emits/consumes, so the mesh knows the
event graph — and the audit-logger module are the next pieces.

Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF

src/index.ts

@@ -8,4 +8,5 @@ export * from "./contracts/index.js";
 export * as tools from "./tools/index.js";
 export * as provisioner from "./provisioner/index.js";
 export * as messaging from "./messaging/index.js";
+export * as events from "./events/index.js";
 export * as primitives from "./primitives/index.js";