AGENTS.md still carried pre-reform Key Rules (mandatory alphabetical
ordering, "quality over quantity" lanes-era language, no prune-sweep
commit exception, no live-verification rule). Bring it in line with
CLAUDE.md and CONTRIBUTING.md: downloads-descending tier ordering,
3+2 cap, sweep-commit exception, verification rule. Also record the
UV_PYTHON=3.13 workaround for Python-3.14-only machines in both files'
Makefile notes, and complete CLAUDE.md's Makefile target list.
Co-Authored-By: Claude <noreply@anthropic.com>
Vinta ChenandClaude