refactor(all): use let chains to flatten nested if statements

Replace nested if and if let blocks with combined if statements using let
chains. This reduces indentation and improves readability across the
project.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (gemma-4-31B-it-UD-Q4_K_XL.gguf)

src/draw.rs

@@ -167,11 +167,10 @@ fn draw(f: &mut Frame, app: &App) {
     if matches!(app.mode, AppMode::Help) {
         f.render_widget(HelpWidget::new(app.help_page), size);
     }
-    if matches!(app.mode, AppMode::ImportWizard) {
-        if let Some(wizard) = &app.wizard {
+    if matches!(app.mode, AppMode::ImportWizard)
+        && let Some(wizard) = &app.wizard {
             f.render_widget(ImportWizardWidget::new(wizard), size);
         }
-    }
     // ExportPrompt now uses the minibuffer at the bottom bar.
     if app.is_empty_model() && matches!(app.mode, AppMode::Normal | AppMode::CommandMode { .. }) {
         draw_welcome(f, main_chunks[1]);