renamed main_page -> main; error message wording

stand.py

@@ -87,7 +87,7 @@ def update_grids(evt):
 
 
 @ui.page("/")
-def main_page():
+def main():
     with ui.column().classes("absolute-center items-center"):
         username = app.storage.user.get("username", "unknown user")
         ui.label(f"Hello {username}!").classes("text-2xl")
@@ -142,7 +142,7 @@ def table_show(pgroup):
 def table_deny(pgroup):
     with ui.column().classes("absolute-center items-center gap-8"):
         ui.icon("sym_o_front_hand", size="xl")
-        ui.label(f"{pgroup} verboten!").classes("text-2xl")
+        ui.label(f"access to {pgroup} denied").classes("text-2xl")
 
 
 @router.post("/{pgroup}/append")