feat(grpc): proper tool result relay via tokio::select

session_chat_via_orchestrator now:
- Spawns generation on a background task
- Reads in_stream for client tool results in foreground
- Forwards results to orchestrator.submit_tool_result()
- Uses tokio::select! to handle both concurrently
- Uses GenerateRequest + Metadata (no transport types in orchestrator)
- Calls grpc::bridge (not orchestrator::grpc_bridge)

src/main.rs

@@ -307,6 +307,13 @@ async fn main() -> anyhow::Result<()> {
     if config.grpc.is_some() {
         let orchestrator_id = state.conversation_registry.get_agent_id().await
             .unwrap_or_default();
+        let orch = Arc::new(orchestrator::Orchestrator::new(
+            config.clone(),
+            state.responder.tools(),
+            state.mistral.clone(),
+            state.conversation_registry.clone(),
+            system_prompt_text.clone(),
+        ));
         let grpc_state = std::sync::Arc::new(grpc::GrpcState {
             config: config.clone(),
             tools: state.responder.tools(),
@@ -315,6 +322,7 @@ async fn main() -> anyhow::Result<()> {
             matrix: matrix_client.clone(),
             system_prompt: system_prompt_text.clone(),
             orchestrator_agent_id: orchestrator_id,
+            orchestrator: Some(orch),
         });
         tokio::spawn(async move {
             if let Err(e) = grpc::start_server(grpc_state).await {