fix(cache): switch to sort_by_key for LRU ordering (#131)

Clippy 1.95 flags the explicit `sort_by` closure as
unnecessary_sort_by when the comparator is a plain Ord on a single
key. Using sort_by_key is shorter and lets the compiler avoid the
extra closure indirection.

Author: SuperKali

src-tauri/src/cache.rs

@@ -128,7 +128,7 @@ fn get_cached_files_by_age_internal() -> Result<Vec<CacheEntry>, String> {
     }
 
     // Sort by modification time (oldest first for LRU eviction)
-    files.sort_by(|a, b| a.modified.cmp(&b.modified));
+    files.sort_by_key(|a| a.modified);
 
     Ok(files)
 }