refactor: Improved type hints, various fixes, removes loguru hijacks

[tazlin]

Of note:

• loadModelManagers deprecated, replaced by load_model_managers
• load_model_managers expects Iterable[str | MODEL_CATEGORY_NAMES | type[BaseModelManager] instead of keyword arguments
• Adhoc LoRa fetch time increased to 45 seconds
• Utilizes the changes in refactor: better test confinement, fix: backwards compat. with download_all_models() horde-model-reference#29 to use AIWORKER_CACHE_HOME to as the location to store model reference files
• Removes the loguru hijack's (init_ok, etc). The worker side still has them, and in practice I cannot discern the difference. I know this may be a contentious choice.
• Better type hints

Everything should be largely backwards compatible if third parties happen to be using this library.