halkyon_ui's FoldingTabs: the tab row under the app bar's title at the
top, scrolling away with the content, the chosen tab's name then small
under the title, which, tapped, scrolls back up to the row, as Strava's.
Learn's Profile (Profile, Statistics) is built on it, and Train's
Profile in tabs: Progress (your body, the last 12 weeks, this year),
Days, and Plans where the device doesn't record.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>