Lesson 7 — Context: windows, sessions, and what the model cannot see
Unit I · Substrate and mechanism

L07_window.py                                student     Teaching stand-in: a 40-word context window loses an earlier fact; the same conversation with a 200-word window keeps it.

Python 3.11 or newer. Standard library only. Run each program from the folder the lesson tells you to put it in:
    python <file>.py        (Windows)
    python3 <file>.py       (macOS and Linux)
