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/model/alert.go

@@ -0,0 +1,25 @@
+package model
+
+import "time"
+
+type AlertRule struct {
+	ID        string    `json:"id"`
+	DeviceID  string    `json:"device_id"`
+	Metric    string    `json:"metric"`
+	Operator  string    `json:"operator"`
+	Threshold float64   `json:"threshold"`
+	Duration  int       `json:"duration"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
+type Alert struct {
+	ID        string    `json:"id"`
+	DeviceID  string    `json:"device_id"`
+	RuleID    string    `json:"rule_id"`
+	Metric    string    `json:"metric"`
+	Value     float64   `json:"value"`
+	Message   string    `json:"message"`
+	Status    string    `json:"status"`
+	CreatedAt time.Time `json:"created_at"`
+	ResolvedAt *time.Time `json:"resolved_at,omitempty"`
+}