Symptom Model

interface Symptom {
  id: string;                    // Unique identifier
  type: string;                  // Symptom type code
  severity: SeverityLevel;       // Current severity
  state: SymptomState;           // Current state
  subject: {
    type: 'asset' | 'device';    // Subject type
    id: string;                  // Subject identifier
  };
  detected_at: string;           // ISO 8601 timestamp
  updated_at: string;            // Last update timestamp
  acknowledged_at?: string;      // When acknowledged
  resolved_at?: string;          // When resolved
  assigned_to?: string;          // Assigned operator
  context: Record<string, any>;  // Detection context
  notes: Note[];                 // Operator notes
  history: StateChange[];        // State history
}

interface Note {
  id: string;
  author: string;
  content: string;
  created_at: string;
}

interface StateChange {
  from_state: SymptomState;
  to_state: SymptomState;
  timestamp: string;
  actor: string;  // User or 'system'
  reason?: string;
}