A workspace video's URL changed on every re-sign and every workspace mutation, so
a paused preview reloaded to its first frame after read-only commands. Media asset
URLs now carry a stat-based content revision (device, inode, size, mtime, ctime),
the video preview keys on it instead of the workspace mutation id, and the player
holds its loaded source until that revision changes. Older servers without the
revision keep the mutation-id behavior.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>