Creates metadata for a dictionary-like type with string keys using source-generated resolution for nested values.
protected static TomlTypeInfo<TDictionary> CreateSourceGeneratedDictionaryTypeInfo<TDictionary, TValue>(TomlSerializerContext context)
where TDictionary : IEnumerable<KeyValuePair<string, TValue>>
This method avoids reflection-based metadata resolution, making it compatible with trimming and NativeAOT.