Replaces the per-video live report subscription (one pool.sub per visible
video × ~20 relays, re-fired on every reconnect — the ~1000 REQ/s storm) with
ONE batched SubscriptionManager subscription over the whole active id set,
updated in place as the set changes. Backfill fetches history only for
newly-added ids (one batched list()). Unchanged sets are a no-op (dedup guard).
MODERATION_REPORT_SUBS_ENABLED flipped back on. Trusted-mute subs were already
batched-by-author, so the relay cap + contact-loop fix already tamed them.
Legacy per-id path retained only for SubscriptionManager-less environments
(unit tests / mock clients). All 39 moderation tests pass; new cheat-resistant
batching test added; nip07-heat shows reports no longer storm (steady idle).
Co-Authored-By: Claude Opus 4.8 <[email protected]>
