fix(generator): use CustomDeserializer instead of CustomSerializer for deserializer prefix

Fixed a critical bug where DeserializerGenerator was incorrectly checking CustomSerializer instead of CustomDeserializer when determining the prefix for deserializer methods. This caused incorrect method resolution for types with custom deserializers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: JasonXuDeveloper

src/Nino.Generator/Common/DeserializerGenerator.cs

@@ -50,8 +50,8 @@ private void GenerateGenericRegister(StringBuilder sb, string name, HashSet<ITyp
                     if (registeredTypes.Add(baseType.TypeSymbol))
                     {
                         var baseTypeName = baseType.TypeSymbol.GetDisplayString();
-                        prefix = !string.IsNullOrEmpty(baseType.CustomSerializer)
-                            ? $"{baseType.CustomSerializer}."
+                        prefix = !string.IsNullOrEmpty(baseType.CustomDeserializer)
+                            ? $"{baseType.CustomDeserializer}."
                             : "";
                         var method = baseType.TypeSymbol.IsInstanceType() ? $"{prefix}DeserializeImpl" : "null";
                         var methodRef = baseType.TypeSymbol.IsInstanceType() ? $"{prefix}DeserializeImplRef" : "null";