feat(autocomplete): group relative-path results by folder (#1091)

Autocomplete suggestions were ranked purely by relevance across the whole
library, so same-named loras from different subfolders interleaved and were
hard to tell apart. Results are now bucketed by folder (root first, then
alphabetically, with nested paths sorting naturally) while keeping the
existing relevance ordering within each folder group.

py/services/base_model_service.py

@@ -1295,6 +1295,27 @@ class BaseModelService(ABC):
             path_for_sorting,
         )
 
+    @staticmethod
+    def _relative_path_folder_group_sort_key(
+        relative_path: str, include_terms: List[str]
+    ) -> tuple:
+        """Group paths by folder, then sort by relevance within each group.
+
+        Folders are ordered alphabetically (case-insensitive) by their full
+        folder path, with root-level files (empty folder) first. Within a
+        folder, paths keep the relevance ordering of
+        ``_relative_path_sort_key``. This keeps same-folder entries together
+        in the autocomplete dropdown instead of interleaving them by filename.
+        """
+        path_for_sorting = BaseModelService._remove_model_extension(
+            relative_path.lower()
+        )
+        folder = path_for_sorting.rpartition(os.sep)[0]
+
+        return (folder,) + BaseModelService._relative_path_sort_key(
+            relative_path, include_terms
+        )
+
     async def search_relative_paths(
         self,
         search_term: str,
@@ -1404,9 +1425,13 @@ class BaseModelService(ABC):
             ):
                 matching_paths.append(relative_path)
 
-        # Sort by relevance (prefix and earliest hits first, then by length and alphabetically)
+        # Group by folder (root first, then alphabetically) and sort by
+        # relevance (prefix and earliest hits, then length and alphabetically)
+        # within each folder group.
         matching_paths.sort(
-            key=lambda relative: self._relative_path_sort_key(relative, include_terms)
+            key=lambda relative: self._relative_path_folder_group_sort_key(
+                relative, include_terms
+            )
         )
 
         # Apply offset and limit