Let the workbook override the output folder and filename via a named cell

Add an optional per-workbook override for the export destination. If the workbook contains a named range (e.g. TablePop_Output) and its cell is not blank, TablePop uses that value as the output folder and/or file name for this workbook. If the name doesn't exist or the cell is blank, fall back to the settings in the TablePop setup screens.

Should accept a folder path, a file name, or a full path, and support the existing placeholders ({TableName}, {Date}, …). Blank or invalid values must fall back silently rather than producing a broken file name.