refactor: clean up gallery tooling and document the workflow

scripts/lib/elo.js

@@ -99,6 +99,20 @@ function syncEloWithMeals(meals) {
   return syncedData;
 }
 
+function getEloAlignmentReport(meals, eloData) {
+  const mealIds = new Set(meals.map((meal) => meal.id));
+  const eloIds = new Set(eloData.entries.map((entry) => entry.id));
+
+  return {
+    missingEntryIds: meals
+      .map((meal) => meal.id)
+      .filter((mealId) => !eloIds.has(mealId)),
+    unexpectedEntryIds: eloData.entries
+      .map((entry) => entry.id)
+      .filter((entryId) => !mealIds.has(entryId)),
+  };
+}
+
 function compareRankedMeals(left, right) {
   if (right.rating !== left.rating) {
     return right.rating - left.rating;
@@ -132,6 +146,7 @@ function getRankedMeals(meals, eloData) {
 
 module.exports = {
   eloPath,
+  getEloAlignmentReport,
   getRankedMeals,
   loadEloData,
   saveEloData,