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/device.go

@@ -0,0 +1,75 @@
+package handler
+
+import (
+	"net/http"
+	"pc-monitor-server/service"
+
+	"github.com/gin-gonic/gin"
+)
+
+type DeviceHandler struct {
+	service *service.DeviceService
+}
+
+func NewDeviceHandler(service *service.DeviceService) *DeviceHandler {
+	return &DeviceHandler{service: service}
+}
+
+type RegisterRequest struct {
+	Hostname string `json:"hostname" binding:"required"`
+	OS       string `json:"os" binding:"required"`
+	IP       string `json:"ip" binding:"required"`
+}
+
+func (h *DeviceHandler) Register(c *gin.Context) {
+	var req RegisterRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	device, err := h.service.Register(req.Hostname, req.OS, req.IP)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"device": device})
+}
+
+func (h *DeviceHandler) GetAll(c *gin.Context) {
+	devices, err := h.service.GetAll()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"devices": devices})
+}
+
+func (h *DeviceHandler) GetByID(c *gin.Context) {
+	id := c.Param("id")
+	device, err := h.service.GetByID(id)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Device not found"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"device": device})
+}
+
+func (h *DeviceHandler) Delete(c *gin.Context) {
+	id := c.Param("id")
+	if err := h.service.Delete(id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "Device deleted"})
+}
+
+func (h *DeviceHandler) Heartbeat(c *gin.Context) {
+	id := c.Param("id")
+	if err := h.service.Heartbeat(id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "OK"})
+}