Consolidate the public interface

[thiagomajesk]

The original idea of this library was to detach the auto-generated underlying spec from the public interface to avoid unexpected breaking changes. That's why we created the structs you see in lib/langfuse_sdk/tracing.

We use those structs to create and update the Langfuse entities, but not when we fetch or list them. We should have a standardized way of consuming this library by either:

• Finding a good way to map everything back to the public interface so the caller can trust to use the same "object" for every operation

  • Open question: Would a common interface between all operations be enough? What about additional metadata?
  • Open question: It's a little more work to maintain going forward since we are also maintaining custom code

• Relax things by accepting plain maps as params and going full on the generated code (maybe getting rid of the Generated namespace in the process)

  • Open question: Exposing the auto-generated code might introduce breaking changes upon regeneration, are we ok with this?
  • Open questions: Tests can potentially break with auto-generated code, which is both good and bad. Good because if we have tests we can properly take action, bad because we are maintaining auto-generated code

PS.: The current implementation was heavily influenced by the TS SDK, so we keep taking some inspiration from them.