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

scenarios/tools-confluence.yml

@@ -9,7 +9,7 @@
 # built lazily and never throws at registration, so the runtime logs `[mesh-tools] serving 3 tool(s)`
 # and binds its serve queues regardless; a tool would only fail if it were actually invoked.
 #
-#   MESH_LAB_HOST_BINARY=.../mesh-host   MESH_LAB_BUNDLE=.../examples/substrate-first-node.lock
+#   MESH_LAB_HOST_BINARY=.../mesh-host   MESH_LAB_BUNDLE=.../examples/foundation-first-node.lock
 #   scripts/build-module-runtime.sh confluence builds mesh-runtime-confluence:development into the
 #   local daemon, which the machine pulls from the internet over its uplink. confluence
 #   needs no service image — it is tools-only.
@@ -29,7 +29,7 @@ machines:
     cpus: 2
 
 images:
-  - mesh-control:development
+  - mesh-controller:development
   # confluence's runtime, built by scripts/build-module-runtime.sh confluence into the local daemon
   # and loaded onto the machine, which holds it by its own image ID. There is no
   # service image: confluence is tools-only and outbound-only.