Recapture every screen through the branch-only mock backend
(tools/screenshot-mock) so the app runs unmodified against real CC/Blender
content: the rows no longer repeat thumbnails (Continue watching, New local
videos and My videos draw different slices), the account has an avatar, the
player sits on a frame with something happening, and the Subscribe button reads
correctly. Adds a channel-page screenshot (banner, stats, Subscribe, full video
grid) and references it in the README.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
