test(tui-core): add unit tests for UiState state machine (#2450)
Add 25 unit tests covering the previously untested UiState::reduce
state machine and snapshot:
- Default state verification
- Key navigation: pane switching (1-5), unknown key no-op
- Prompt lifecycle: pending_tasks increment, response delta tracking
- Tool lifecycle: active_tool set/clear, pending_tasks decrement, saturation
- Job lifecycle: active_jobs increment/decrement, progress clamping, saturation
- Approval lifecycle: pending_approvals increment/decrement, saturation
- Pause/Resume: flag toggling
- Tick: ScheduleBackgroundRefresh effect
- Snapshot: field presence, state change reflection
Co-authored-by: Hu Qiantao <huqiantao@HudeMacBook-Air.local>
HUQIANTAO
74a8a6f808