Fix second audit findings and restore crash detection dialog

src/core/duplicates.rs

@@ -329,6 +329,8 @@ fn build_name_group(name: &str, records: &[&AppImageRecord]) -> DuplicateGroup {
 }
 
 /// Compare two version strings for ordering.
+/// Falls back to lexicographic comparison of cleaned versions to guarantee
+/// the total ordering contract (antisymmetry) required by sort_by.
 fn compare_versions(a: &str, b: &str) -> std::cmp::Ordering {
     use super::updater::{clean_version, version_is_newer};
 
@@ -339,8 +341,11 @@ fn compare_versions(a: &str, b: &str) -> std::cmp::Ordering {
         std::cmp::Ordering::Equal
     } else if version_is_newer(a, b) {
         std::cmp::Ordering::Greater
-    } else {
+    } else if version_is_newer(b, a) {
         std::cmp::Ordering::Less
+    } else {
+        // Neither is newer (unparseable components) - use lexicographic fallback
+        ca.cmp(&cb)
     }
 }