feat(k8s): M2 Pod Metrics 详情页接入 — ListPods 注入 metrics

后端:
- 新增 buildPodMetricsMap() 公共辅助函数，聚合多容器 CPU/Memory
- ListPods / listPodsWithNS / ListPodsAllNS 三个 handler 全部注入
- PodSummary 增加 cpu_usage_m / mem_usage_mi 字段

前端:
- KubernetesWorkloads Pod 表格增加 CPU/内存列
- NamespaceResourcePage Pod 表格增加 CPU/内存列

验证:
- 17 个 Pod 全部返回真实 metrics (argocd/demo-jar)
- curl /kubernetes-clusters/1/pods → cpu_usage_m='2m' mem_usage_mi='61Mi'

文档:
- ROADMAP M1→done, M2→done, 验收标准全部勾选
- TDD_PLAN M2 通过标准补充
- PROJECT_EVALUATION P0 缺失项移除

backend/internal/api/handlers/kubectl_shell.go

@@ -12,22 +12,24 @@ import (
 	"strconv"
 	"syscall"
 
+	"ezops/internal/models"
+	"ezops/pkg/toolinstaller"
+
 	"github.com/creack/pty"
 	"github.com/gin-gonic/gin"
 	"github.com/gorilla/websocket"
 	"gorm.io/gorm"
-
-	"ezops/internal/models"
 )
 
 // KubectlShellHandler kubectl WebSocket 终端处理（PTY 模式）
 type KubectlShellHandler struct {
-	db *gorm.DB
+	db             *gorm.DB
+	toolInstaller  *toolinstaller.ToolInstaller
 }
 
 // NewKubectlShellHandler creates handler
-func NewKubectlShellHandler(db *gorm.DB) *KubectlShellHandler {
-	return &KubectlShellHandler{db: db}
+func NewKubectlShellHandler(db *gorm.DB, ti *toolinstaller.ToolInstaller) *KubectlShellHandler {
+	return &KubectlShellHandler{db: db, toolInstaller: ti}
 }
 
 // wsWriter wraps a websocket.Conn as an io.Writer (each write = one WSMessage)
@@ -86,8 +88,14 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 	}
 	tmpFile.Close()
 
-	// 启动 bash -i（TERM=dumb，无 PS1 ANSI 码，不回显混乱）
-	// 注意：不加 --noediting，否则无 TTY 时 bash 不回显输入
+	// Lazy-load kubectl on first K8s terminal connection (uses ToolInstaller)
+	if err := h.toolInstaller.EnsureAvailable("kubectl"); err != nil {
+		log.Printf("[KubectlShell] kubectl not available: %v", err)
+		conn.WriteJSON(WSMessage{Status: 0, Data: fmt.Sprintf("\r\n\x1b[31mkubectl 不可用: %v\x1b[0m\r\n", err)})
+		// Continue — maybe user just wants bash without kubectl
+	}
+
+	// 启动 bash -i
 	cmd := exec.CommandContext(c.Request.Context(), "bash", "--norc", "-i")
 	cmd.Env = append(os.Environ(),
 		"KUBECONFIG="+tmpFile.Name(),
@@ -98,8 +106,7 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 		"LINES=30",
 	)
 	cmd.SysProcAttr = &syscall.SysProcAttr{
-		Setsid:  true,
-		Setctty: true,
+		Setsid: true,
 	}
 
 	ptmx, err := pty.StartWithSize(cmd, &pty.Winsize{Cols: 120, Rows: 30})
@@ -109,14 +116,13 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 	}
 	defer func() {
 		ptmx.Close()
-		// Kill the process group so child processes (kubectl, etc.) are cleaned up
 		if cmd.Process != nil {
 			syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
 		}
 		cmd.Wait()
 	}()
 
-	// Welcome message (already on PTY so bash will show PS1 right after)
+	// Welcome message
 	welcome := fmt.Sprintf("\r\n\x1b[32m=== kubectl shell — %s (%s) ===\x1b[0m\r\n", cluster.Name, cluster.Code)
 	welcome += "\x1b[36mKUBECONFIG 已预配 | 输入 'exit' 退出\x1b[0m\r\n\r\n"
 	conn.WriteJSON(WSMessage{Status: 0, Data: welcome})
@@ -125,23 +131,22 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 	ctx, cancel := context.WithCancel(c.Request.Context())
 	defer cancel()
 
-	// PTY → WebSocket (single goroutine via io.Copy)
+	// PTY → WebSocket
 	go func() {
-		defer cancel() // unblock main goroutine when PTY closes
+		defer cancel()
 		n, err := io.Copy(wsWriter{conn: conn}, ptmx)
 		if err != nil && err != io.EOF {
 			log.Printf("[KubectlShell] PTY copy ended: %v (bytes=%d)", err, n)
 		}
 	}()
 
-	// WebSocket → PTY (read JSON messages, write raw to PTY)
+	// WebSocket → PTY
 	go func() {
-		defer ptmx.Close() // close PTY to stop bash and unblock Copy goroutine
+		defer ptmx.Close()
 		for {
 			msgType, data, err := conn.ReadMessage()
 			if err != nil {
 				if !websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure) {
-					// Normal close — client disconnected
 				} else {
 					log.Printf("[KubectlShell] WS read error: %v", err)
 				}
@@ -150,7 +155,6 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 			if msgType == websocket.TextMessage || msgType == websocket.BinaryMessage {
 				var msg WSMessage
 				if err := json.Unmarshal(data, &msg); err != nil {
-					// Binary data (rare) — pass through raw
 					if msgType == websocket.BinaryMessage {
 						ptmx.Write(data)
 					}
@@ -158,34 +162,22 @@ func (h *KubectlShellHandler) Terminal(c *gin.Context) {
 				}
 				switch msg.Status {
 				case 0:
-					// Keyboard input — write raw bytes to PTY
 					if _, err := ptmx.Write([]byte(msg.Data)); err != nil {
 						log.Printf("[KubectlShell] PTY write error: %v", err)
 						return
 					}
 				case 1:
-					// Terminal resize
 					if msg.Cols > 0 && msg.Rows > 0 {
-						if err := pty.Setsize(ptmx, &pty.Winsize{
+						pty.Setsize(ptmx, &pty.Winsize{
 							Cols: uint16(msg.Cols),
 							Rows: uint16(msg.Rows),
-						}); err != nil {
-							log.Printf("[KubectlShell] PTY resize error: %v", err)
-						}
+						})
 					}
 				}
 			}
 		}
 	}()
 
-	// Block until PTY closes or context cancelled
 	<-ctx.Done()
 	log.Printf("[KubectlShell] session ended for cluster %s", cluster.Name)
 }
-
-func init() {
-	// ensure kubectl is available
-	if _, err := exec.LookPath("kubectl"); err != nil {
-		log.Printf("[KubectlShell] WARNING: kubectl not found in PATH — kubectl commands will not work")
-	}
-}