Remove unused methods in AsymmetricUCB

[speculator19]

I noticed these two methods in shinka/llm/dynamic_sampling.py that don't seem to be used anywhere:

• _add_to_reward (lines 204-213)
• _multiply_reward (lines 215-221)

Did a thorough search and couldn't find any calls to them. They've been there since the initial commit but never actually used. Looks like the code just uses _logadd() and regular operators instead of these methods.

[RobertTLange]

Thank you for taking a close look @speculator19 -- really appreciated. Will clean this up. FYI: We will release a refactor of the LLM prioritization soon, which pulls out the posterior calculation from the LLMClient. This will make it cleaner and potentially supports applying the logic to other parts of the codebase.

Feel free to let me know about your experience and other features you would like to see (improve).