a0b26fc1aa
- Added 'plan' model role option to support architectural planning with dedicated model selection via CLI argument (--plan), environment variable (OMP_PLAN_MODEL), and UI menu action. - Updated model selector to display 'PLAN' badge for plan models and prioritize them in the model sorting order. - Relaxed task management constraints to allow multiple tasks to be in_progress simultaneously, enabling parallel task execution instead of enforcing single-task-at-a-time workflow. - Improved todo validation to check for blocking pending tasks before allowing a todo to be marked in_progress, with more specific error messages indicating which earlier tasks are blocking progress.