fix config corruption when deleting the last commented mask or zone (#23627)

Deleting the last entry of a mapping or sequence via config/set orphaned ruamel's comment tokens, which were then emitted above a flow-style {} / [] at column 0, which is unparseable yaml that failed validation and silently rolled the change back. The fix is to clear the emptied collection's stale comment metadata (and the parent's entry for it) so the dump stays valid. Non-empty collections are left untouched so sibling comments are preserved. This covers both emptied maps and emptied lists.

frigate/util/builtin.py

@@ -293,26 +293,51 @@ def update_yaml_file_bulk(file_path: str, updates: Dict[str, Any]):
         logger.error(f"Unable to write to Frigate config file {file_path}: {e}")
 
 
+def clear_orphaned_comments(collection, parent, parent_key) -> None:
+    """Drop stale ruamel comment tokens after a deletion empties a collection.
+
+    When the last entry of a mapping or sequence is removed, any comments that
+    lived inside that collection's block are orphaned. ruamel then emits them
+    above a flow-style `{}`/`[]` dedented to column 0, which is unparseable and
+    corrupts the config. Clearing the emptied collection's own comment metadata
+    (and the parent's entry pointing at it) keeps the dump valid. Non-empty
+    collections are left untouched so comments on remaining siblings survive.
+    """
+    if not hasattr(collection, "ca") or len(collection) != 0:
+        return
+
+    collection.ca.items.clear()
+    collection.ca.comment = None
+    if parent is not None and hasattr(parent, "ca"):
+        parent.ca.items.pop(parent_key, None)
+
+
 def update_yaml(data, key_path, new_value):
     temp = data
+    parent = None
+    parent_key = None
     for key in key_path[:-1]:
         if isinstance(key, tuple):
             if key[0] not in temp:
                 temp[key[0]] = [{}] * max(1, key[1] + 1)
             elif len(temp[key[0]]) <= key[1]:
                 temp[key[0]] += [{}] * (key[1] - len(temp[key[0]]) + 1)
+            parent, parent_key = temp[key[0]], key[1]
             temp = temp[key[0]][key[1]]
         else:
             if key not in temp or temp[key] is None:
                 temp[key] = {}
+            parent, parent_key = temp, key
             temp = temp[key]
 
     last_key = key_path[-1]
     if new_value == "":
         if isinstance(last_key, tuple):
             del temp[last_key[0]][last_key[1]]
+            clear_orphaned_comments(temp[last_key[0]], temp, last_key[0])
         else:
             del temp[last_key]
+            clear_orphaned_comments(temp, parent, parent_key)
     else:
         if isinstance(last_key, tuple):
             if last_key[0] not in temp: