Read data from Excel worksheet with cell metadata including validation rules.

Args:
    filepath: Path to Excel file
    sheet_name: Name of worksheet
    start_cell: Starting cell (default A1)
    end_cell: Ending cell (optional, auto-expands if not provided)
    preview_only: Whether to return preview only

Returns:  
JSON string containing structured cell data with validation metadata.
Each cell includes: address, value, row, column, and validation info (if any).

Write data to Excel worksheet.
Excel formula will write to cell without any verification.

PARAMETERS:  
filepath: Path to Excel file
sheet_name: Name of worksheet to write to
data: List of lists containing data to write to the worksheet, sublists are assumed to be rows
start_cell: Cell to start writing to, default is "A1"

Get all data validation rules in a worksheet.

This tool helps identify which cell ranges have validation rules
and what types of validation are applied.

Args:
    filepath: Path to Excel file
    sheet_name: Name of worksheet
    
Returns:
    JSON string containing all validation rules in the worksheet