After packaging, stage the bare AniTrack-linux-amd64 binary (the updater swaps os.Executable in place; the user tarball single top-level directory would fail the single-entry rule), sign it with wails3 updater sign using UPDATER_SIGNING_KEY (missing secret is a hard error, key shredded after use), split the output into .sha512/.sig sidecars, and extend the idempotent replace-upload loop from 1 asset to all 4. Tarball flow untouched; rc tags get signed assets too, which the beta-channel live proof needs.