- Add comprehensive mission CLI commands: create, list, show, start, abort, delete, and next
- Add Pi extension tools for mission operations: list_missions, show_mission, start_mission, abort_mission
- Implement mission-aware scheduler with task start handling and autoAdvance support
- Add sliceId to Task type and autoAdvance flag to Mission type for slice sequencing
- Add MissionStore helper methods for mission lifecycle operations
- Include comprehensive tests for CLI commands and Pi extension mission tools
