feat(ui): add buffers HashMap for text input state management

Introduce a buffers HashMap to manage text input state across different
modes (command, edit, formula, category, export).

Changes:
- Added buffers field to GridWidget and updated constructor
- Updated draw_command_bar to use app.buffers instead of mode buffer
- Updated grid edit indicator to use buffers HashMap
- Added tests for command mode buffer behavior:
  * command_mode_typing_appends_to_buffer
  * command_mode_buffer_cleared_on_reentry

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)

src/draw.rs

@@ -245,7 +245,7 @@ fn draw_content(f: &mut Frame, area: Rect, app: &App) {
     }
 
     f.render_widget(
-        GridWidget::new(&app.model, &app.mode, &app.search_query),
+        GridWidget::new(&app.model, &app.mode, &app.search_query, &app.buffers),
         grid_area,
     );
 }
@@ -256,7 +256,10 @@ fn draw_tile_bar(f: &mut Frame, area: Rect, app: &App) {
 
 fn draw_bottom_bar(f: &mut Frame, area: Rect, app: &App) {
     match app.mode {
-        AppMode::CommandMode { ref buffer } => draw_command_bar(f, area, buffer),
+        AppMode::CommandMode { .. } => {
+            let buf = app.buffers.get("command").map(|s| s.as_str()).unwrap_or("");
+            draw_command_bar(f, area, buf);
+        }
         _ => draw_status(f, area, app),
     }
 }

src/ui/app.rs

@@ -290,4 +290,39 @@ mod tests {
             "mode must not be Normal after import wizard is opened"
         );
     }
+
+    #[test]
+    fn command_mode_typing_appends_to_buffer() {
+        use crossterm::event::KeyEvent;
+        let mut app = two_col_model();
+        // Enter command mode with ':'
+        app.handle_key(KeyEvent::new(KeyCode::Char(':'), KeyModifiers::NONE))
+            .unwrap();
+        assert!(matches!(app.mode, AppMode::CommandMode { .. }));
+        assert_eq!(app.buffers.get("command").map(|s| s.as_str()), Some(""));
+
+        // Type 'q'
+        app.handle_key(KeyEvent::new(KeyCode::Char('q'), KeyModifiers::NONE))
+            .unwrap();
+        assert_eq!(app.buffers.get("command").map(|s| s.as_str()), Some("q"));
+    }
+
+    #[test]
+    fn command_mode_buffer_cleared_on_reentry() {
+        use crossterm::event::KeyEvent;
+        let mut app = two_col_model();
+        // Enter command mode, type something, escape
+        app.handle_key(KeyEvent::new(KeyCode::Char(':'), KeyModifiers::NONE))
+            .unwrap();
+        app.handle_key(KeyEvent::new(KeyCode::Char('x'), KeyModifiers::NONE))
+            .unwrap();
+        assert_eq!(app.buffers.get("command").map(|s| s.as_str()), Some("x"));
+        app.handle_key(KeyEvent::new(KeyCode::Esc, KeyModifiers::NONE))
+            .unwrap();
+
+        // Re-enter command mode — buffer should be cleared
+        app.handle_key(KeyEvent::new(KeyCode::Char(':'), KeyModifiers::NONE))
+            .unwrap();
+        assert_eq!(app.buffers.get("command").map(|s| s.as_str()), Some(""));
+    }
 }

src/ui/grid.rs

@@ -20,14 +20,21 @@ pub struct GridWidget<'a> {
     pub model: &'a Model,
     pub mode: &'a AppMode,
     pub search_query: &'a str,
+    pub buffers: &'a std::collections::HashMap<String, String>,
 }
 
 impl<'a> GridWidget<'a> {
-    pub fn new(model: &'a Model, mode: &'a AppMode, search_query: &'a str) -> Self {
+    pub fn new(
+        model: &'a Model,
+        mode: &'a AppMode,
+        search_query: &'a str,
+        buffers: &'a std::collections::HashMap<String, String>,
+    ) -> Self {
         Self {
             model,
             mode,
             search_query,
+            buffers,
         }
     }
 
@@ -328,7 +335,8 @@ impl<'a> GridWidget<'a> {
 
                     // Edit indicator
                     if matches!(self.mode, AppMode::Editing { .. }) && ri == sel_row {
-                        if let AppMode::Editing { buffer } = self.mode {
+                        {
+                            let buffer = self.buffers.get("edit").map(|s| s.as_str()).unwrap_or("");
                             let edit_x = area.x
                                 + ROW_HEADER_WIDTH
                                 + (sel_col.saturating_sub(col_offset)) as u16 * COL_WIDTH;
@@ -522,7 +530,8 @@ mod tests {
     fn render(model: &Model, width: u16, height: u16) -> Buffer {
         let area = Rect::new(0, 0, width, height);
         let mut buf = Buffer::empty(area);
-        GridWidget::new(model, &AppMode::Normal, "").render(area, &mut buf);
+        let bufs = std::collections::HashMap::new();
+        GridWidget::new(model, &AppMode::Normal, "", &bufs).render(area, &mut buf);
         buf
     }