feat(tui): introduce comprehensive state management for TUI interface

- Add AppStateRest as the central state struct for managing TUI state.
- Implement InputState for handling user input, autocomplete, and history.
- Create MiscState to manage overlays, notifications, and editor state.
- Introduce ScrollState for viewport scrolling functionality.
- Develop TranscriptCache for efficient message rendering in the chat pane.
- Implement SimpleAgent and SimpleWorkflowEngine for agent lifecycle management.
- Add helper functions for managing effort levels and token counting.
- Organize state-related modules for better maintainability and clarity.

apps/interfaces/tui/src/view/overlays/usage.rs

@@ -31,7 +31,7 @@ pub fn render(
     let summary = runtime.map(|r| compute_usage_summary(&r.usage, r.session_start, now_ms));
     let (edit_count, lesson_count, review_count, consec_empty) =
         runtime.map_or((0, 0, 0, 0), |r| {
-            (r.edit_count, r.lesson_count, r.review_count, r.consecutive_empty_reviews)
+            (r.edit_count, r.lessons.total, r.review_count, r.consecutive_empty_reviews)
         });
     let mut lines = vec![
         Line::from(Span::styled(