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/alert.go

@@ -0,0 +1,89 @@
+package handler
+
+import (
+	"net/http"
+	"pc-monitor-server/model"
+	"pc-monitor-server/service"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+type AlertHandler struct {
+	service *service.AlertService
+}
+
+func NewAlertHandler(service *service.AlertService) *AlertHandler {
+	return &AlertHandler{service: service}
+}
+
+type CreateRuleRequest struct {
+	DeviceID  string  `json:"device_id" binding:"required"`
+	Metric    string  `json:"metric" binding:"required"`
+	Operator  string  `json:"operator" binding:"required"`
+	Threshold float64 `json:"threshold" binding:"required"`
+	Duration  int     `json:"duration"`
+}
+
+func (h *AlertHandler) CreateRule(c *gin.Context) {
+	var req CreateRuleRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	rule := &model.AlertRule{
+		ID:        uuid.New().String(),
+		DeviceID:  req.DeviceID,
+		Metric:    req.Metric,
+		Operator:  req.Operator,
+		Threshold: req.Threshold,
+		Duration:  req.Duration,
+		CreatedAt: time.Now(),
+	}
+
+	if err := h.service.CreateRule(rule); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"rule": rule})
+}
+
+func (h *AlertHandler) GetRulesByDevice(c *gin.Context) {
+	deviceID := c.Param("id")
+	rules, err := h.service.GetRulesByDevice(deviceID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"rules": rules})
+}
+
+func (h *AlertHandler) DeleteRule(c *gin.Context) {
+	id := c.Param("id")
+	if err := h.service.DeleteRule(id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "Rule deleted"})
+}
+
+func (h *AlertHandler) GetActiveAlerts(c *gin.Context) {
+	alerts, err := h.service.GetActiveAlerts()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"alerts": alerts})
+}
+
+func (h *AlertHandler) ResolveAlert(c *gin.Context) {
+	id := c.Param("id")
+	if err := h.service.ResolveAlert(id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"message": "Alert resolved"})
+}