feat(brahman-demo): bootstrap script reproducible — broker + producer + consumer + 4 explorers

Iter 22. Cierra el set de hoy: future-me (o cualquier nuevo collab)
levanta el escenario completo con un comando.

crates/apps/brahman-demo/ con 3 binarios:
- brahman-demo-broker: Server::bind standalone con Broker. Reemplaza
  a ente-zero para demos (ente-zero es PID 1 con kernel surface,
  child subreaper, bus, brain, audit — overkill).
- brahman-demo-producer: Card con flow.output[demo-stream:json].
- brahman-demo-consumer: Card con flow.input[demo-feed:json] —
  mismo type → matchea con producer.

Env vars en los 3: BRAHMAN_INIT_SOCKET, BRAHMAN_BROKER_CONTEXT,
BRAHMAN_DEMO_LABEL/FLOW/TYPE, RUST_LOG.

scripts/bootstrap-demo.sh:
- Modes: all (default) / broker / only.
- Cleanup-safe: trap mata todos los PIDs spawneados (SIGTERM grace
  + SIGKILL fallback) y borra el socket.
- Espera al socket antes de spawnear (evita ENOENT en handshake).
- Logs separados por proceso bajo $BRAHMAN_DEMO_LOG_DIR.

Smoke end-to-end (sin DISPLAY): consumer recibe MatchEvent
{ Available, demo-feed ← demo-stream, via: Exact, pinned: false }
automáticamente cuando entra el producer. Match fluye por el push
channel del broker.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -1288,6 +1288,20 @@ dependencies = [
  "yahweh-meta-schema",
 ]
 
+[[package]]
+name = "brahman-demo"
+version = "0.1.0"
+dependencies = [
+ "brahman-broker",
+ "brahman-card",
+ "brahman-handshake",
+ "brahman-sidecar",
+ "tokio",
+ "tracing",
+ "tracing-subscriber",
+ "ulid",
+]
+
 [[package]]
 name = "brahman-handshake"
 version = "0.1.0"