feat: add access log functionality and related components

- Introduced NodeAccessLog model and corresponding database migrations.
- Implemented access log retrieval in the service layer.
- Created API endpoint for accessing logs with appropriate security measures.
- Developed frontend components for displaying access logs, including filtering and summary statistics.
- Updated observability buffer to include access logs and ensure proper merging and retention.
- Enhanced traffic report and observability tests to validate new access log features.
- Updated documentation to reflect changes in access log handling and data retention policies.

atsf_server/model/node_access_log.go

@@ -0,0 +1,30 @@
+package model
+
+import "time"
+
+type NodeAccessLog struct {
+	ID         uint      `json:"id" gorm:"primaryKey"`
+	NodeID     string    `json:"node_id" gorm:"index;size:64;not null"`
+	LoggedAt   time.Time `json:"logged_at" gorm:"index"`
+	RemoteAddr string    `json:"remote_addr" gorm:"size:128"`
+	Host       string    `json:"host" gorm:"size:255"`
+	Path       string    `json:"path" gorm:"size:2048"`
+	StatusCode int       `json:"status_code"`
+	RawJSON    string    `json:"raw_json" gorm:"type:text"`
+	CreatedAt  time.Time `json:"created_at"`
+}
+
+func ListNodeAccessLogs(nodeID string, since time.Time, limit int) (logs []*NodeAccessLog, err error) {
+	query := DB.Order("logged_at desc, id desc")
+	if nodeID != "" {
+		query = query.Where("node_id = ?", nodeID)
+	}
+	if !since.IsZero() {
+		query = query.Where("logged_at >= ?", since)
+	}
+	if limit > 0 {
+		query = query.Limit(limit)
+	}
+	err = query.Find(&logs).Error
+	return logs, err
+}