FX.101 SuperCad said "not signed in" for Teams sync although the person was signed in to the site

A SuperCad tab is signed in to the site by a cookie, but the account API takes a key, and nothing in the page fetched one (the add-ons client that does is mounted only for the eight apps and refuses SuperCad). New: POST /api/account/super-connect (same origin, guarded) mints a 30-day sync-scope key for the tab; super-account.js keeps it in the tab, reconnects once on a 401, retries when the tab regains focus, and tells the plug-in at once. Found when the person said they were signed in; my tests had injected a signed-in account object and never exercised this.