Modular Pi instruction sources

../SKILL.md is the committed projection read by Pi. Do not edit it directly.

Edit ../projection.md.tmpl and the ordered Disambiguation/Memory fragments here, then regenerate from harness/:

python -m tht.pi_skill_projection --write

Check that the committed projection is current with:

python -m tht.pi_skill_projection --check

Composition order is the static FRAGMENT_ORDER tuple in tht/pi_skill_projection.py; the generator never discovers files from the directory.