Deduplicate campaign reward references

src/game/state/campaignState.ts

@@ -905,6 +905,18 @@ function uniqueStrings(value: unknown): string[] {
   ].slice(0, maxCampaignStringListEntries);
 }
 
+function uniqueByKey<T>(entries: T[], keyForEntry: (entry: T) => string) {
+  const seen = new Set<string>();
+  return entries.filter((entry) => {
+    const key = keyForEntry(entry);
+    if (!key || seen.has(key)) {
+      return false;
+    }
+    seen.add(key);
+    return true;
+  });
+}
+
 function normalizeKeyString(value: unknown): string {
   if (typeof value !== 'string') {
     return '';
@@ -1658,21 +1670,27 @@ function cloneCampaignRewardSnapshot(rewards?: CampaignRewardSnapshot): Campaign
     supplies: uniqueStrings(rewardRecord.supplies),
     equipment: uniqueStrings(rewardRecord.equipment),
     reputation: uniqueStrings(rewardRecord.reputation),
-    recruits: arrayOrEmpty<unknown>(rewardRecord.recruits)
-      .filter(isPlainObject)
-      .map((recruit) => ({
-        unitId: normalizeKeyString(recruit.unitId),
-        name: normalizeDisplayString(recruit.name)
-      }))
-      .filter((recruit) => recruit.unitId && recruit.name)
+    recruits: uniqueByKey(
+      arrayOrEmpty<unknown>(rewardRecord.recruits)
+        .filter(isPlainObject)
+        .map((recruit) => ({
+          unitId: normalizeKeyString(recruit.unitId),
+          name: normalizeDisplayString(recruit.name)
+        }))
+        .filter((recruit) => recruit.unitId && recruit.name),
+      (recruit) => recruit.unitId
+    )
       .slice(0, maxCampaignStringListEntries),
-    unlocks: arrayOrEmpty<unknown>(rewardRecord.unlocks)
-      .filter(isPlainObject)
-      .map((unlock) => ({
-        battleId: normalizeKeyString(unlock.battleId),
-        title: normalizeDisplayString(unlock.title)
-      }))
-      .filter((unlock) => unlock.battleId && unlock.title)
+    unlocks: uniqueByKey(
+      arrayOrEmpty<unknown>(rewardRecord.unlocks)
+        .filter(isPlainObject)
+        .map((unlock) => ({
+          battleId: normalizeKeyString(unlock.battleId),
+          title: normalizeDisplayString(unlock.title)
+        }))
+        .filter((unlock) => unlock.battleId && unlock.title),
+      (unlock) => unlock.battleId
+    )
       .slice(0, maxCampaignStringListEntries),
     note: note.length > 0 && note.length <= maxCampaignRewardNoteLength ? note : undefined
   };