Interactive /explain-diff walkthrough of the phone_focus_mode hotspot/tethering
enforcer (commit range HEAD~2..HEAD): background on netfilter OUTPUT vs FORWARD,
the second-phone bypass and fix, a steppable FORWARD-chain simulator, and a
debiased 5-question quiz. Refresh the explanations gallery index.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Q6i3cdhKBoUrKxy4rmx6hH
