d47ef8c committed the design-decisions half of the 10.12.40.0/22 / 10.12.88.0/22 ruling
but not the CURRENT-STATE block: the editing step failed its own assertion and the shell
chain did not gate the commit on it -- the same masking as the earlier | tail red-lint
push. Corrected forward, not by rewriting pushed history.

Records the ruling, the measured pattern (the dc0->dc1 offset is a consequence of dc0's
historical 20-28 gap, not a rule), why that gap is unusable (20+60=80 and 20+48=68 both
allocated), and that the v4 half is ruled-and-not-built and gates nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf