Adds the Phase M planning entry: replace the happy-path WorldSession
shape with a holtburger-aligned reliable network stack while keeping
acdream's stricter checksum verification + live ACE compatibility.
Lays out M.1–M.x sub-lanes (audit/parity map, layer extraction,
reliability core, etc.).
Detailed spec to land at
docs/superpowers/specs/2026-05-02-network-stack-conformance.md
before implementation starts. Holtburger is the client-behavior
oracle for this phase.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>