app.py: xplicitly checks for the DASHBOARD_FROM_RESULTS_DIR environment variable when from_results_dir is None, ensuring the correct directory is used even if Click's auto_envvar_prefix mechanism isn't working as expected.
app.py: fix ensures that if from_results_dir is used, the dashboard loads the parquet file from the correct location (inside the results directory) instead of looking for it in the current working directory.
app.py: fix missing benchmarks.parquet error. strip the prefix for local files and pass a simple relative path to pd.read_parquet. This ensures the path is interpreted correctly as relative to the current working directory.
