- Enforced tool decision in plan mode--agent now requires calling either `ask` or `exit_plan_mode` when a turn ends without a required tool call.
- Fixed cancellation behavior of `ask` tool to abort the current turn instead of returning a normal cancelled selection, while timeout-driven auto-cancel still returns without aborting.
- Added plan-mode-tool-decision-reminder system prompt to guide agent when required tools are not called.
- Improved agent_end event handling to use fallback assistant message when #lastAssistantMessage is unavailable.