Rename mesh-control -> mesh-controller, substrate -> foundation

One name per thing, per the HQ glossary: the module/container/image/binary/repo
becomes mesh-controller, the seat the-controller, and the store+broker pair the
foundation (embedded base bundles, default template and example lock renamed with
their go:embed directives). No behaviour change — a pure vocabulary rename.

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

src/main.ts

@@ -32,7 +32,7 @@ import { emit } from "@novox/mesh-sdk/events";
 
 /**
  * Connect the way this process is meant to: with its sealed credential if the mesh gave it one, and
- * over the plain bootstrap URL otherwise. A scoped module assumes the substrate's exchanges exist —
+ * over the plain bootstrap URL otherwise. A scoped module assumes the foundation's exchanges exist —
  * its account may not declare them (ADR 0043).
  */
 async function connectBroker(): Promise<Broker> {