docs(plan): stream-realtime production campaign — gap register + RG0–RG6 gates (#157)

The CTO blueprint to lift PORTAL_REALTIME=stream from experimental to
production-ready, on par with the proven Portal-backfill evidence discipline.

Contents: correctness gap register (RT-G1–RT-G15) with per-gap severity and
test cites — validating/correcting the reorg/finalize logic (RT-G3/G4/G5/G6/G9
already mutation-tested; cited) and isolating the real gaps: a liveness cluster
(RT-G8 #48 teardown, RT-G10 silent-tip stall, RT-G11 unbounded realtime read,
RT-G12 delivery-gated finalize poll → RT-1) and one suspected correctness bug
(RT-G13 isolated-cutover finality floor → RT-2, verify-first). Evidence gates
RG0–RG6 with concrete acceptance numbers (≥200 chaos kills / 100% clean
resumes / byte-identical digests; ≥72h multichain soak; 7-day A/B + patched-build
re-soak), sequencing that leaves the in-flight soak untouched pre-2026-07-13,
INV-22/INV-23 candidates, and the single atomic README label flip at RG6.

Full autonomy granted (execution is GO; the label flip's gate transferred to the
evidence dossier). This doc is the campaign's single source of truth.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: dzhelezov