The portal needs to show an agency which playlists it may post to. New read surface on the
security primitive, built with write-path rigor: the confinement query lives in
lib/agency-targets.js (own token + bound workspace only) and is bite-tested four ways -
own targets yes; another token's, outside the allowlist, and cross-workspace all NO;
neutralizing the t.token_id filter makes it go red. Real-path wiring + the portal's
graceful 401 trigger asserted in the integration suite. No :playlistId, so router.param
doesn't apply - the query is the seam.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>