added mhtml support and fixed some bugs in the process

SYS/pipeline.py

@@ -1983,6 +1983,8 @@ class PipelineExecutor:
         command_expanded = False
         example_selector_triggered = False
         normalized_source_cmd = str(source_cmd or "").replace("_", "-").strip().lower()
+        prefer_row_action = False
+        preferred_row_action = None
 
         if normalized_source_cmd in HELP_EXAMPLE_SOURCE_COMMANDS and selection_indices:
             try:
@@ -2011,8 +2013,6 @@ class PipelineExecutor:
             else:
                 selected_row_args: List[str] = []
                 skip_pipe_expansion = source_cmd in {".pipe", ".mpv"} and len(stages) > 0
-                prefer_row_action = False
-                preferred_row_action = None
                 if len(selection_indices) == 1 and not stages:
                     try:
                         row_action = _get_row_action(selection_indices[0])