fix cross-repo path deps; remove el compiler from neuron-lang/

- neuron-runtime, neuron-store, neuron-migrate: fix path deps
  (products/engram/ → foundation/engram/engrams/, products/el/ → foundation/el/engrams/)
- neuron-rs workspace: fix axon-events/axon-protocol paths
  (../../../platform/ → ../../platform/, paths were off by one level)
- neuron-lang/compiler/ removed (el self-hosting compiler now lives in foundation/el/el-compiler/)

neuron-lang/events/bus.el

@@ -0,0 +1,17 @@
+// events/bus.el — Event bus. Three primitives over native_queue_*.
+//
+// Publish, consume, ack. Consumer identity IS the subscription.
+// No separate subscribe step. No state. Intelligence lives in el.
+// The Rust backend is swappable: InMemory → Engram → Kafka → RabbitMQ.
+
+fn event_publish(topic: String, payload: String) -> Void {
+    native_queue_publish(topic, payload)
+}
+
+fn event_consume(topic: String, consumer: String) -> String {
+    return native_queue_consume(topic, consumer)
+}
+
+fn event_ack(topic: String, consumer: String, msg_id: String) -> Void {
+    native_queue_ack(topic, consumer, msg_id)
+}