Whether the session can change its turn-taking / auto-response mode on a live socket (no
reconnect) via IRealtimeSession.Reconfigure. true for providers with a runtime-mutable
session config (OpenAI session.update); false where it's fixed at connect (Gemini Live).
Static capability flags of a live IRealtimeSession, for container introspection (the realtime- session analogue of
IBridgeProviderFeatures). Grow this as providers gain runtime abilities — each new flag defaults to "unsupported" for any driver that hasn't declared it, so the container stays safe.