Incident docs: 2 appendix-A entries, platform-traps MAC-regen corollary, LP draft ...

Closes the remaining documentation queue from the 2026-07-21
commissioning incident. Appendix-A gains the MAC-drift and
agent-resolver symptoms (verbatim, with checks + recorded fixes);
platform-traps 1e gains the unpinned-MAC regeneration corollary + index
row; LP draft ready for the operator to file (sanitization warning
included). Still queued: stale pod cleanup at stage close.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STHXiHfoxHqq8fGRVvb66G