[O2B-1533] Add JSDoc and other comment describing DetectorOrders priorities

Author: isaachilly

lib/public/domain/enums/DetectorOrders.js

@@ -13,6 +13,14 @@
 
 import { DetectorType } from './DetectorTypes.js';
 
+/**
+ * Defines priority mappings for detector types.
+ * Each key is a mapping between {@link DetectorType} values and their numeric priority
+ * (larger values will appear first - see detectorsProvider LN88).
+ *
+ * - **DEFAULT**: Standard ordering used across most views.
+ * - **RCT**: Ordering used in the Run Condition Table, which prioritizes PHYSICAL detectors.
+ */
 export const DetectorOrders = Object.freeze({
     DEFAULT: {
         [DetectorType.OTHER]: 0,

lib/public/services/detectors/detectorsProvider.js

@@ -85,6 +85,7 @@ export class DetectorsProvider extends RemoteDataProvider {
             if (specialPair.includes(detector1.name) && specialPair.includes(detector2.name)) {
                 return detector1.name === 'ZDC' ? 1 : -1;
             }
+            // Note the negative sign to have larger priority types appear first
             return -(typeToOrderingKey(detector1.type) - typeToOrderingKey(detector2.type)) * 10 + detector1.name.localeCompare(detector2.name);
         };