Add userState query

backend/app/Savor22b/GraphTypes/Query/Query.cs

@@ -27,6 +27,27 @@ public Query(BlockChain blockChain, Swarm? swarm = null)
         _blockChain = blockChain;
         _swarm = swarm;
 
+        Field<UserStateType>(
+            "userState",
+            description: "The specified address's user state",
+            arguments: new QueryArguments(
+                new QueryArgument<NonNullGraphType<StringGraphType>>
+                {
+                    Name = "address",
+                    Description = "The account holder's 40-hex address",
+                }
+            ),
+            resolve: context =>
+            {
+                var accountAddress = new Address(context.GetArgument<string>("address"));
+                var rootStateEncoded = blockChain.GetState(accountAddress);
+                RootState rootState = rootStateEncoded is Bencodex.Types.Dictionary bdict
+                    ? new RootState(bdict)
+                    : new RootState();
+                return rootState;
+            }
+        );
+
         Field<StringGraphType>(
             "asset",
             description: "The specified address's balance in MNT.",