Second pure piece of the "My Videos" tab: collapseUserVideos reduces all of a
user's video events (every edit/revert/deletion the client holds) to one entry
per addressable video, keeping the latest version — which carries the current
state, including deleted:true when the latest is a tombstone (those are gone from
the active feed but still matter here for storage cleanup). Filters to the owner
only, drops invalid notes, sorts newest-first.
Tests + mutation-verified: owner filtering, dedup-to-latest, deleted-latest
preserved, re-publish-after-delete wins, invalid dropped, empty-pubkey returns
nothing (never leak all videos). Flipping latest->oldest fails 3 scenarios.
Build + full lint green.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
