Excel to YAML/Register RTL

Call the registered excel_yml_gen MCP tool with excel_file, sheet_name, and optional output_dir. If omitted, output goes to <excel-stem>_generated/ beside the workbook, never inside the plugin package.

Workbook sheets:

• <name>: component/protocol/base-address configuration
• <name>_reg: register definitions
• <name>_intp: optional interrupts

Passing <name>_reg automatically selects the three-sheet group. Outputs include YAML, bus register-file RTL, an instance wrapper, and a TDR buffer list. Use references/excel2yml_demo.xlsx as the format example.

Generation uses argument-vector subprocess execution; never reintroduce shell-string execution for paths supplied by users.