# Task: Implement a Stack Class

Implement a `Stack` class in `workspace/stack.py` that provides a standard stack (LIFO) data structure.

## Requirements

The `Stack` class must support the following methods:

1. `push(item)` -- Push an item onto the top of the stack.
2. `pop()` -- Remove and return the top item. Raise `IndexError` with message "pop from empty stack" if the stack is empty.
3. `peek()` -- Return the top item without removing it. Raise `IndexError` with message "peek at empty stack" if the stack is empty.
4. `is_empty()` -- Return `True` if the stack has no items, `False` otherwise.
5. `size()` -- Return the number of items currently in the stack.

## Output

Save the file to `workspace/stack.py`.
