- Subtasks now inherit parent task's executor and validator model settings
- When triage creates subtasks, modelProvider/modelId and validatorModelProvider/validatorModelId are copied from parent
- Clean up legacy mission-store code (mission-store.ts, mission-types.ts, and related tests)
- Add comprehensive tests for subtask model inheritance in triage, routes, and db
- Remove obsolete changeset for missions-database-schema
