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/ui/app.rs

@@ -374,13 +374,12 @@ impl App {
     }
 
     pub fn autosave_if_needed(&mut self) {
-        if self.dirty && self.last_autosave.elapsed() > Duration::from_secs(30) {
-            if let Some(path) = &self.file_path.clone() {
+        if self.dirty && self.last_autosave.elapsed() > Duration::from_secs(30)
+            && let Some(path) = &self.file_path.clone() {
                 let ap = persistence::autosave_path(path);
                 let _ = persistence::save(&self.model, &ap);
                 self.last_autosave = Instant::now();
             }
-        }
     }
 
     pub fn start_import_wizard(&mut self, json: serde_json::Value) {