fix: register PeerCenterRpc in management API server so CLI peer-center works (#1929)

PeerCenterRpc was only registered in the per-instance peer-to-peer RPC
manager (domain = network_name), but not in the management API server
(domain = ""). The CLI connects to the management API with an empty
domain, causing "Invalid service name: PeerCenterRpc" errors.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

easytier/src/rpc_service/peer_center.rs

@@ -0,0 +1,108 @@
+use std::sync::Arc;
+
+use crate::{
+    instance_manager::NetworkInstanceManager,
+    proto::{
+        peer_rpc::{
+            GetGlobalPeerMapRequest, GetGlobalPeerMapResponse, PeerCenterRpc, ReportPeersRequest,
+            ReportPeersResponse,
+        },
+        rpc_types::controller::BaseController,
+    },
+};
+
+#[derive(Clone)]
+pub struct PeerCenterManageRpcService {
+    instance_manager: Arc<NetworkInstanceManager>,
+}
+
+impl PeerCenterManageRpcService {
+    pub fn new(instance_manager: Arc<NetworkInstanceManager>) -> Self {
+        Self { instance_manager }
+    }
+}
+
+#[async_trait::async_trait]
+impl PeerCenterRpc for PeerCenterManageRpcService {
+    type Controller = BaseController;
+
+    async fn get_global_peer_map(
+        &self,
+        ctrl: BaseController,
+        req: GetGlobalPeerMapRequest,
+    ) -> crate::proto::rpc_types::error::Result<GetGlobalPeerMapResponse> {
+        let instance_service =
+            super::get_instance_service(&self.instance_manager, &None).map_err(|e| {
+                let msg = e.to_string();
+                if msg.contains("please specify the instance ID") {
+                    anyhow::anyhow!(
+                        "PeerCenter management RPC cannot select an instance automatically \
+                         when multiple instances are running; please use an API that allows \
+                         specifying an instance identifier."
+                    )
+                } else {
+                    e
+                }
+            })?;
+
+        instance_service
+            .get_peer_center_service()
+            .get_global_peer_map(ctrl, req)
+            .await
+    }
+
+    async fn report_peers(
+        &self,
+        _: BaseController,
+        _: ReportPeersRequest,
+    ) -> crate::proto::rpc_types::error::Result<ReportPeersResponse> {
+        Err(anyhow::anyhow!("not implemented for management API").into())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{
+        instance_manager::NetworkInstanceManager,
+        proto::{
+            peer_rpc::{GetGlobalPeerMapRequest, ReportPeersRequest},
+            rpc_types::controller::BaseController,
+        },
+    };
+
+    fn make_service() -> PeerCenterManageRpcService {
+        PeerCenterManageRpcService::new(Arc::new(NetworkInstanceManager::new()))
+    }
+
+    #[tokio::test]
+    async fn get_global_peer_map_errors_when_no_instance() {
+        let svc = make_service();
+        let result = svc
+            .get_global_peer_map(
+                BaseController::default(),
+                GetGlobalPeerMapRequest::default(),
+            )
+            .await;
+        assert!(result.is_err());
+        let msg = result.unwrap_err().to_string();
+        assert!(
+            msg.contains("No instance matches the selector"),
+            "unexpected error: {msg}"
+        );
+    }
+
+    #[tokio::test]
+    async fn report_peers_always_returns_error() {
+        let svc = make_service();
+        let result = svc
+            .report_peers(BaseController::default(), ReportPeersRequest::default())
+            .await;
+        assert!(result.is_err());
+        let msg = result.unwrap_err().to_string();
+        assert!(
+            msg.contains("not implemented for management API"),
+            "unexpected error: {msg}"
+        );
+    }
+}