feat: abgen-registry feature flag to switch AB registry + CDN

Adds the `abgen-registry` flag and a ResolveAssetBundleUrl seam in
DecentralandUrlsSource that, when enabled, routes AssetBundleRegistry and
AssetBundlesCDN (and all registry-derived endpoints) to their `-abgen`
sibling hosts, taking precedence over OPTIMIZED_ASSETS. FeatureFlagsDependent
caching; CLI --optimized-assets-url override still wins; LODs are not routed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dalkia

Explorer/Assets/DCL/FeatureFlags/FeatureFlagsStrings.cs

@@ -90,6 +90,12 @@ public static class FeatureFlagsStrings
         public const string HARDWARE_FINGERPRINT = "alfa-hardware-fingerprint";
         public const string OPTIMIZED_ASSETS = "optimized-assets";
         public const string OPTIMIZED_ASSETS_BASE_URL_VARIANT = "assets-base-url";
+
+        // Routes the asset-bundle registry + CDN to their `-abgen` parallel-pipeline
+        // siblings (own registry, ab-cdn-abgen CDN). Takes precedence over
+        // OPTIMIZED_ASSETS so the whole AB surface moves together. See
+        // DecentralandUrlsSource.ResolveAssetBundleUrl.
+        public const string ABGEN_REGISTRY = "abgen-registry";
         public const string USE_CUSTOM_MEDIA_PLAYER_WINDOWS = "use-custom-media-player-windows";
         public const string USE_CUSTOM_MEDIA_PLAYER_MAC_SILICON = "use-custom-media-player-mac-silicon";
         public const string USE_CUSTOM_MEDIA_PLAYER_MAC_INTEL = "use-custom-media-player-mac-intel";

Explorer/Assets/DCL/NetworkDefinitions/Browser/DecentralandUrlsSource.cs

@@ -216,6 +216,36 @@ private UrlData ResolveOptimizedAssetsUrl(string dedicatedHostUrl)
             return new UrlData(CacheBehaviour.FeatureFlagsDependent, $"https://abcdn.decentraland.{ENV}");
         }
 
+        /// <summary>
+        ///     Asset-bundle registry / CDN base resolution. When the abgen parallel-pipeline flag is on,
+        ///     routes to the `-abgen` sibling host (own registry + ab-cdn-abgen CDN), taking precedence over
+        ///     OPTIMIZED_ASSETS so the whole AB surface (registry + CDN) moves together. The CLI
+        ///     "--optimized-assets-url" override still wins. LODs are intentionally NOT routed here (abgen's
+        ///     LOD lane is unimplemented) — LodGeneratorCDN keeps calling ResolveOptimizedAssetsUrl directly.
+        /// </summary>
+        private UrlData ResolveAssetBundleUrl(string dedicatedHostUrl)
+        {
+            if (optimizedAssetsBaseOverride is { Length: > 0 })
+                return new UrlData(CacheBehaviour.FeatureFlagsDependent, optimizedAssetsBaseOverride);
+
+            FeatureFlagsConfiguration featureFlags = FeatureFlagsConfiguration.Instance;
+
+            // FeatureFlagsDependent so the abgen host is re-resolved (not cached) until flags load — the
+            // {ENV} token is substituted in Url() once the environment domain is applied.
+            if (!featureFlags.IsEmpty && featureFlags.IsEnabled(FeatureFlagsStrings.ABGEN_REGISTRY))
+                return new UrlData(CacheBehaviour.FeatureFlagsDependent, InsertAbgenSubdomain(dedicatedHostUrl));
+
+            return ResolveOptimizedAssetsUrl(dedicatedHostUrl);
+        }
+
+        /// <summary>
+        ///     Inserts the `-abgen` label into the leading subdomain of an AB host, leaving the {ENV} token
+        ///     intact: `https://ab-cdn.decentraland.{ENV}` → `https://ab-cdn-abgen.decentraland.{ENV}`,
+        ///     `https://asset-bundle-registry.decentraland.{ENV}` → `https://asset-bundle-registry-abgen.decentraland.{ENV}`.
+        /// </summary>
+        private static string InsertAbgenSubdomain(string hostUrl) =>
+            hostUrl.Replace(".decentraland.", "-abgen.decentraland.");
+
         /// <summary>Registry-composed endpoints inherit the registry base's caching so a flag-driven base is not cached early.</summary>
         private UrlData ComposeRegistryUrl(string path) =>
             new (RawUrl(DecentralandUrl.AssetBundleRegistry).Caching, $"{Url(DecentralandUrl.AssetBundleRegistry)}{path}");
@@ -273,7 +303,7 @@ protected virtual UrlData RawUrl(DecentralandUrl decentralandUrl) =>
                 DecentralandUrl.Account => $"https://decentraland.{ENV}/account/",
                 DecentralandUrl.MinimumSpecs => $"https://docs.decentraland.{ENV}/player/FAQs/decentraland-101/#what-hardware-do-i-need-to-run-decentraland",
                 DecentralandUrl.Market => $"https://market.decentraland.{ENV}",
-                DecentralandUrl.AssetBundlesCDN => ResolveOptimizedAssetsUrl($"https://ab-cdn.decentraland.{ENV}"),
+                DecentralandUrl.AssetBundlesCDN => ResolveAssetBundleUrl($"https://ab-cdn.decentraland.{ENV}"),
                 DecentralandUrl.LodGeneratorCDN => ResolveOptimizedAssetsUrl($"https://lod-generator-unity-cdn.decentraland.{ENV}"),
                 DecentralandUrl.ArchipelagoStatus => $"https://archipelago-ea-stats.decentraland.{ENV}/status",
                 DecentralandUrl.ArchipelagoHotScenes => $"https://archipelago-ea-stats.decentraland.{ENV}/hot-scenes",
@@ -286,7 +316,7 @@ protected virtual UrlData RawUrl(DecentralandUrl decentralandUrl) =>
                 DecentralandUrl.CameraReelLink => $"https://reels.decentraland.{ENV}",
                 DecentralandUrl.Blocklist => $"https://config.decentraland.{ENV}/denylist.json",
                 DecentralandUrl.ApiFriends => $"wss://rpc-social-service-ea.decentraland.{ENV}",
-                DecentralandUrl.AssetBundleRegistry => ResolveOptimizedAssetsUrl($"https://asset-bundle-registry.decentraland.{ENV}"),
+                DecentralandUrl.AssetBundleRegistry => ResolveAssetBundleUrl($"https://asset-bundle-registry.decentraland.{ENV}"),
 
                 DecentralandUrl.AssetBundleRegistryVersion => ComposeRegistryUrl("/entities/versions"),
                 DecentralandUrl.MarketplaceClaimName => $"https://decentraland.{ENV}/marketplace/names/claim",