Function compile_page_debug 

pub fn compile_page_debug(
    entry_path: &str,
    files: &HashMap<String, String>,
    mock_data_json: &str,
    file_origins: &HashMap<String, String>,
) -> Result<String, String>

Like compile_page, but with debug HTML comments at component/slot boundaries.

file_origins maps file paths to theme names for debug comment attribution.