feat: 添加 Node 领域类型和 NodesService

包含 Node、UpdateNodeMsg、AcctGatherEnergy、ExtSensorsData、PowerMgmtData 等类型。NodesService 提供 GetNodes、GetNode、PostNode、DeleteNode 4 个方法，并定义 NodeFlag* 常量。

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/slurm/slurm_nodes_test.go

@@ -0,0 +1,163 @@
+package slurm
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestNodesService_GetNodes(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/nodes", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		fmt.Fprint(w, `{"nodes": []}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	resp, _, err := client.Nodes.GetNodes(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected non-nil response")
+	}
+}
+
+func TestNodesService_GetNodes_WithOptions(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/nodes", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		q := r.URL.Query()
+		if q.Get("update_time") != "12345" {
+			t.Errorf("expected update_time=12345, got %s", q.Get("update_time"))
+		}
+		if q.Get("flags") != NodeFlagDetail {
+			t.Errorf("expected flags=%s, got %s", NodeFlagDetail, q.Get("flags"))
+		}
+		fmt.Fprint(w, `{"nodes": []}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	opts := &GetNodesOptions{
+		UpdateTime: Ptr("12345"),
+		Flags:      Ptr(NodeFlagDetail),
+	}
+	resp, _, err := client.Nodes.GetNodes(context.Background(), opts)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected non-nil response")
+	}
+}
+
+func TestNodesService_GetNode(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/node/node1", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		fmt.Fprint(w, `{"nodes": [{"name": "node1"}]}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	resp, _, err := client.Nodes.GetNode(context.Background(), "node1", nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected non-nil response")
+	}
+	if resp.Nodes == nil || len(*resp.Nodes) != 1 {
+		t.Fatalf("expected 1 node, got %v", resp.Nodes)
+	}
+	if resp.Nodes == nil || (*resp.Nodes)[0].Name == nil || *(*resp.Nodes)[0].Name != "node1" {
+		t.Errorf("expected name=node1, got %v", resp.Nodes)
+	}
+}
+
+func TestNodesService_PostNode(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/node/node1", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "POST")
+		if ct := r.Header.Get("Content-Type"); ct != "application/json" {
+			t.Errorf("expected Content-Type application/json, got %s", ct)
+		}
+		fmt.Fprint(w, `{}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	update := &UpdateNodeMsg{
+		Comment: Ptr("updated comment"),
+	}
+	resp, _, err := client.Nodes.PostNode(context.Background(), "node1", update)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected non-nil response")
+	}
+}
+
+func TestNodesService_DeleteNode(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/node/node1", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "DELETE")
+		fmt.Fprint(w, `{}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	resp, _, err := client.Nodes.DeleteNode(context.Background(), "node1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if resp == nil {
+		t.Fatal("expected non-nil response")
+	}
+}
+
+func TestNodesService_GetNode_Error(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/node/nonexistent", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+		fmt.Fprint(w, `{"errors": [{"error": "node not found"}]}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	_, _, err := client.Nodes.GetNode(context.Background(), "nonexistent", nil)
+	if err == nil {
+		t.Fatal("expected error for 404 response")
+	}
+	if !strings.Contains(err.Error(), "404") {
+		t.Errorf("expected error to contain 404, got %v", err)
+	}
+}
+
+func TestNodesService_GetNodes_Error(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/slurm/v0.0.40/nodes", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprint(w, `{"errors": [{"error": "internal error"}]}`)
+	})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, _ := NewClient(server.URL, nil)
+	_, _, err := client.Nodes.GetNodes(context.Background(), nil)
+	if err == nil {
+		t.Fatal("expected error for 500 response")
+	}
+}