fix: add allow(clippy::derivable_impls) to BrowserBackend::default()

Author: claude

core/src/config.rs

@@ -335,6 +335,7 @@ pub enum BrowserBackend {
     Lightpanda,
 }
 
+#[allow(clippy::derivable_impls)]
 impl Default for BrowserBackend {
     fn default() -> Self {
         BrowserBackend::Chrome