ServiceSettings types were introduced for runtime updates via ServiceUpdateSettingsFrame, but there was tension between init-time and runtime APIs: overlapping-but-different InputParams vs ServiceSettings classes, and runtime-updatable fields like `model` and `voice` scattered as direct init args rather than living in a settings object. This unifies them so developers use the same settings type at both init and runtime, improving ergonomics and consistency.
Every concrete AIService subclass (LLM, TTS, STT, ImageGen, Vision, Video) now accepts a `settings` parameter for runtime-updatable config. Old init args (`model`, `voice_id`, `params`/`InputParams`) still work but emit DeprecationWarnings pointing to the new API. When both are provided, `settings` takes precedence. Leaf classes emit warnings; base classes do not, avoiding double warnings in inheritance chains.
