Model the 2025-11-25 to 2026-07-28 transition as first-class manifest data

Execute the era/supersession pass: 37 new successor entries (the MRTR family
that replaces server-initiated requests, the per-request log-level pair, the
subscriptions/listen family, discover-side successors), all registered
deferred ahead of their tests; 82 existing entries edited - version-wide
2026 arm exclusions on era-retired behaviours become removed_in with a
superseded_by link and an explanatory note (transport-shaped exclusions
stay), no-heir removals get tombstone notes, and the per-request logLevel
divergence is recorded on the three logging entries whose tests pin un-gated
delivery on live 2026 cells. 62 supersession pairs, all bidirectional and
versioned, enforced by the coverage gate at import. The twelve surviving
version-wide exclusions are exactly the documented re-admission checklist.
Cells unchanged (830 before and after).

Author: maxisbey