feat: init pc-monitor project

- Client: Go-based Windows hardware monitoring (CPU, GPU, memory, disk, network, power)
- Server: Go + Gin + SQLite backend with REST API
- Frontend: Vue 3 + Element Plus dashboard
- Docker deployment support
- Windows service installation script

server/api/handler/metrics.go

@@ -0,0 +1,80 @@
+package handler
+
+import (
+	"net/http"
+	"pc-monitor-server/model"
+	"pc-monitor-server/service"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+type MetricsHandler struct {
+	service *service.MetricsService
+}
+
+func NewMetricsHandler(service *service.MetricsService) *MetricsHandler {
+	return &MetricsHandler{service: service}
+}
+
+type ReportRequest struct {
+	DeviceID string `json:"device_id" binding:"required"`
+	model.Metrics
+}
+
+func (h *MetricsHandler) Report(c *gin.Context) {
+	var req ReportRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	metrics := req.Metrics
+	metrics.DeviceID = req.DeviceID
+	metrics.Timestamp = time.Now()
+
+	if err := h.service.Save(&metrics); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "Metrics saved"})
+}
+
+func (h *MetricsHandler) GetLatest(c *gin.Context) {
+	deviceID := c.Param("id")
+	metrics, err := h.service.GetLatest(deviceID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "No metrics found"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"metrics": metrics})
+}
+
+func (h *MetricsHandler) GetHistory(c *gin.Context) {
+	deviceID := c.Param("id")
+
+	startStr := c.Query("start")
+	endStr := c.Query("end")
+
+	start := time.Now().Add(-1 * time.Hour)
+	end := time.Now()
+
+	if startStr != "" {
+		if t, err := time.Parse(time.RFC3339, startStr); err == nil {
+			start = t
+		}
+	}
+	if endStr != "" {
+		if t, err := time.Parse(time.RFC3339, endStr); err == nil {
+			end = t
+		}
+	}
+
+	metrics, err := h.service.GetHistory(deviceID, start, end, 1000)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"metrics": metrics})
+}