PyXLL Add-In Utilities Module

Problem Description

A small team of analysts uses PyXLL to run Python functions directly inside Excel. They want to add two utilities to their PyXLL add-in module:

Utility 1 — Active Sheet Name function: A worksheet function (callable from a cell formula like =ActiveSheetName()) that returns the name of the currently active worksheet. It takes no arguments and should update automatically when recalculated.

Utility 2 — Load CSV menu action: A menu item under a custom ribbon or right-click menu that, when triggered, opens a file-open dialog for the user to pick a CSV file, reads it using Python's csv module, and writes its contents (row by row) into the active worksheet starting at cell A1. The menu action does not need to return a value.

Both utilities need access to the live Excel Application object to read or write worksheet data.

Output Specification

Produce a single Python module file named workbook_helpers.py containing both functions decorated appropriately for PyXLL. The file should be self-contained, requiring only pyxll, win32com, and the Python standard library.