Python SDK 0.9.8

Fixed\n\n- Let the runtime own gateway-managed agent session history so workers do not reload or persist the same conversation through legacy entity storage.\n- Exclude the unresolved assistant tool call that triggered an agent handoff before passing conversation history to the target agent.\n- Make the worker entity-state adapter available while constructing execution contexts.\n\n### Changed\n\n- Align API compatibility and integration tests with the current LM streaming event shape, runtime endpoints, journal event names, and package imports.