Vote Rewards: dedupe provider list on load + idx-aware Vue key

frontend/src/views/SettingsView.vue

@@ -1342,7 +1342,10 @@ onMounted(() => {
             <Card class="settings-card" v-if="voteRewardsSettings.providers && voteRewardsSettings.providers.length > 0">
               <template #title>{{ t('settings.voteRewardsProviderHeader') }}</template>
               <template #content>
-                <div v-for="(provider, idx) in voteRewardsSettings.providers" :key="provider.key" class="provider-block vote-provider">
+                <!-- :key includes idx so duplicate provider keys (legacy state) don't collide
+                     in Vue's v-for diffing. Backend dedups on load now (see EnsureDefaultProviders),
+                     but this is defense in depth for any future regression. -->
+                <div v-for="(provider, idx) in voteRewardsSettings.providers" :key="`${provider.key}-${idx}`" class="provider-block vote-provider">
                   <h3 class="provider-title">{{ voteProviderDisplayName(provider.key) }}</h3>
 
                   <div class="vote-provider-grid">

src/KitsuneCommand/Features/VoteRewardsFeature.cs

@@ -541,6 +541,30 @@ private void LoadPersistedSettings()
         private static void EnsureDefaultProviders(VoteRewardsSettings settings)
         {
             if (settings.Providers == null) settings.Providers = new List<VoteProviderSettings>();
+
+            // Deduplicate by Key. PR #50 prevented NEW duplicates forming (the
+            // Newtonsoft-append bug), but admins whose state was poisoned while
+            // that bug was active still carry the doubled list in their saved
+            // JSON. Strip duplicates here on every load — the entry with the
+            // most "configured" signal wins (enabled + has-api-key > enabled-only
+            // > has-api-key > anything else) so a real config is never displaced
+            // by an empty stub.
+            var beforeCount = settings.Providers.Count;
+            settings.Providers = settings.Providers
+                .Where(p => p != null && !string.IsNullOrWhiteSpace(p.Key))
+                .GroupBy(p => p.Key, StringComparer.OrdinalIgnoreCase)
+                .Select(group => group
+                    .OrderByDescending(p => p.Enabled && !string.IsNullOrEmpty(p.ApiKey))
+                    .ThenByDescending(p => p.Enabled)
+                    .ThenByDescending(p => !string.IsNullOrEmpty(p.ApiKey))
+                    .First())
+                .ToList();
+            var afterCount = settings.Providers.Count;
+            if (afterCount < beforeCount)
+            {
+                Log.Out($"[KitsuneCommand] VoteRewards: deduped {beforeCount - afterCount} duplicate provider entry/entries on load.");
+            }
+
             if (!settings.Providers.Any(p => string.Equals(p.Key, "7daystodie-servers", StringComparison.OrdinalIgnoreCase)))
             {
                 settings.Providers.Add(new VoteProviderSettings { Key = "7daystodie-servers", Enabled = false });