Phase 1 of the on-boarding plan, and the shared layer for unified grid
loading. A video that exists as both a bitvid kind-30078 note and a NIP-71
mirror/original previously could appear twice (e.g. independent dual-posts).
js/utils/videoDeduper.js: collapseCrossEcosystem() groups events by a
per-author identity (fileSha256 / originalFileSha256 / infoHash, plus an
`eid` namespace that links an on-boarded note's `importedFrom` to the
original foreign event) via union-find, and keeps the bitvid-native version
(else newest). dedupeVideos() = root-dedup THEN cross-ecosystem collapse.
Routed through the shared chokepoint app.dedupeVideosByRoot (playback
coordinator), so the feed stage, channel profile, and search all collapse
duplicates identically — "show one, prefer bitvid" everywhere. Channel
fallback path updated too.
Limitation (documented): hash-less independent dual-posts can't be matched
until the bitvid side carries on-board provenance (Phase 2).
Tests + mutation-verified (prefer-bitvid, per-author identity, infohash,
provenance link, root+cross composition). 1262/1263 unit (known flake).
Co-Authored-By: Claude Opus 4.8 <[email protected]>
