Add agentic tool access for Neuron in DHARMA rooms

Adds handle_dharma_room_turn_agentic to chat.el — same full tool loop
as handle_chat_agentic but reads transcript directly (not message), and
returns {response, cgi_id, tools_used} to match the dharma room shape.

Registers dharma_room_turn_agentic as a new event type in routes.el so
the studio can dispatch @neuron turns through this dedicated path.

routes.el

@@ -164,6 +164,10 @@ fn handle_dharma_recv(body: String) -> String {
         return route_health()
     }
 
+    if str_eq(eff_event, "dharma_room_turn_agentic") {
+        return handle_dharma_room_turn_agentic(eff_payload)
+    }
+
     if str_eq(eff_event, "dharma_room_turn") {
         return handle_dharma_room_turn(eff_payload)
     }