refactor: create heartbeats func in HubStore

hub/internal/store/sqlc/gen/models.go

@@ -1,6 +1,6 @@
 // Code generated by sqlc. DO NOT EDIT.
 // versions:
-//   sqlc v1.30.0
+//   sqlc v1.31.1
 
 package gen
 
@@ -19,3 +19,12 @@ type Agent struct {
 	Capabilities *string
 	RegisteredAt time.Time
 }
+
+type Heartbeat struct {
+	ID                 int64
+	AgentID            string
+	CpuUsage           float64
+	MemoryUsage        float64
+	DiskUsage          float64
+	HeartbeatTimestamp time.Time
+}