SearchEngine: Update to use IndexStore.Name()/NameLower()/BuildPath() APIs matching Rust. Remove NameAt/NameLowerAt references that no longer exist.

FastSeekWpf/Core/SearchEngine.cs

@@ -73,7 +73,7 @@ public static class SearchEngine
         return false;
     }
 
-    // Search — matches Rust search() exactly
+    // Search — matches Rust search() exactly. Uses IndexStore.Name() / NameLower() / BuildPath()
     public static List<SearchResult> Search(
         IndexStore store,
         string query,
@@ -132,9 +132,7 @@ public static class SearchEngine
                 if (ext != null && Array.IndexOf(AppExtensions, ext) >= 0)
                 {
                     string pathLower = fullPath.ToLowerInvariant();
-                    if (!ContainsAny(pathLower, AppPathMarkers))
-                        rank = baseRank;
-                    else
+                    if (ContainsAny(pathLower, AppPathMarkers))
                         rank = 0;
                 }
             }