v1.1.8

Features

• Session: Reworked session history storage from Event.model_flags-based model visibility to an active/historical split, with Session.events holding the active model window and Session.historical_events optionally retaining events moved out by max-event filtering, TTL, or summarization.
• Session: Added SessionServiceConfig.store_historical_events, updated Redis, SQL, and InMemory persistence semantics for active/historical events, and kept list APIs lightweight by omitting both active and historical events from list_sessions().
• Session: Optimized summarization by keeping [summary_event, recent_events...] as the new active window and checking only the leading summary anchor instead of repeatedly scanning the event list.
• Model: Added configuration support for OpenAI/Anthropic APIs and LiteLLM prompt cache.

Bug Fixes

• Telemetry: Propagated span context correctly in async generators by using start_span with context attach/detach, and fixed member-agent input tracing to prefer override_messages over user_content.