Drop the duplicate ResolveShard added in the previous commit

CultNetDatabase already had a public ResolveShard(schemaId, key) wrapping
ResolveShardInternal; the previous commit added a second one with the same
signature. CultNetDatabaseServer.CreateSelectionResponse's shardIdOf callback
uses the pre-existing one.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/GameCult.Networking/CultNetDatabase.cs

@@ -513,12 +513,6 @@ namespace GameCult.Networking
         /// </summary>
         public CultNetSelectionCursorKey CursorKey { get; }
 
-        /// <summary>
-        /// Resolves the shard that owns a record key (R-Q: whether a matched selection's rows span more
-        /// than one shard's log, and so whether the page's <c>asOf</c> is well defined).
-        /// </summary>
-        public CultNetShardDescriptor ResolveShard(string schemaId, CultRecordKey key) => ResolveShardInternal(schemaId, key);
-
         /// <summary>
         /// Gets the local cache backing this database surface.
         /// </summary>