feat: 添加 HTTP 处理层和结构化日志

- JobHandler: 提交/查询/取消/历史，5xx Error + 4xx Warn 日志

- ClusterHandler: 节点/分区/诊断，错误和未找到日志

- TemplateHandler: CRUD 操作，创建/更新/删除 Info + 未找到 Warn

- 不记录成功响应（由 middleware.RequestLogger 处理）

- 不记录请求体和模板内容（安全考虑）

- 完整 TDD 测试，使用 zaptest/observer 验证日志级别和字段

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

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

internal/handler/cluster.go

@@ -0,0 +1,94 @@
+package handler
+
+import (
+	"gcy_hpc_server/internal/server"
+	"gcy_hpc_server/internal/service"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+)
+
+// ClusterHandler handles HTTP requests for cluster operations (nodes, partitions, diag).
+type ClusterHandler struct {
+	clusterSvc *service.ClusterService
+	logger     *zap.Logger
+}
+
+// NewClusterHandler creates a new ClusterHandler with the given ClusterService.
+func NewClusterHandler(clusterSvc *service.ClusterService, logger *zap.Logger) *ClusterHandler {
+	return &ClusterHandler{clusterSvc: clusterSvc, logger: logger}
+}
+
+// GetNodes handles GET /api/v1/nodes.
+func (h *ClusterHandler) GetNodes(c *gin.Context) {
+	nodes, err := h.clusterSvc.GetNodes(c.Request.Context())
+	if err != nil {
+		h.logger.Error("handler error", zap.String("method", "GetNodes"), zap.Error(err))
+		server.InternalError(c, err.Error())
+		return
+	}
+
+	server.OK(c, nodes)
+}
+
+// GetNode handles GET /api/v1/nodes/:name.
+func (h *ClusterHandler) GetNode(c *gin.Context) {
+	name := c.Param("name")
+
+	resp, err := h.clusterSvc.GetNode(c.Request.Context(), name)
+	if err != nil {
+		h.logger.Error("handler error", zap.String("method", "GetNode"), zap.Error(err))
+		server.InternalError(c, err.Error())
+		return
+	}
+	if resp == nil {
+		h.logger.Warn("not found", zap.String("method", "GetNode"), zap.String("name", name))
+		server.NotFound(c, "node not found")
+		return
+	}
+
+	server.OK(c, resp)
+}
+
+// GetPartitions handles GET /api/v1/partitions.
+func (h *ClusterHandler) GetPartitions(c *gin.Context) {
+	partitions, err := h.clusterSvc.GetPartitions(c.Request.Context())
+	if err != nil {
+		h.logger.Error("handler error", zap.String("method", "GetPartitions"), zap.Error(err))
+		server.InternalError(c, err.Error())
+		return
+	}
+
+	server.OK(c, partitions)
+}
+
+// GetPartition handles GET /api/v1/partitions/:name.
+func (h *ClusterHandler) GetPartition(c *gin.Context) {
+	name := c.Param("name")
+
+	resp, err := h.clusterSvc.GetPartition(c.Request.Context(), name)
+	if err != nil {
+		h.logger.Error("handler error", zap.String("method", "GetPartition"), zap.Error(err))
+		server.InternalError(c, err.Error())
+		return
+	}
+	if resp == nil {
+		h.logger.Warn("not found", zap.String("method", "GetPartition"), zap.String("name", name))
+		server.NotFound(c, "partition not found")
+		return
+	}
+
+	server.OK(c, resp)
+}
+
+// GetDiag handles GET /api/v1/diag.
+func (h *ClusterHandler) GetDiag(c *gin.Context) {
+	resp, err := h.clusterSvc.GetDiag(c.Request.Context())
+	if err != nil {
+		h.logger.Error("handler error", zap.String("method", "GetDiag"), zap.Error(err))
+		server.InternalError(c, err.Error())
+		return
+	}
+
+	server.OK(c, resp)
+}