Tab Vacuum - click once to remove every duplicate Chrome tab and auto-group the rest by website

I had 4 Chrome windows with ~80 tabs each, mostly duplicates of the same Stack Overflow page. Tried OneTab (saves to a list - not what I wanted) and Workona (cloud sync, overkill). So I wrote ~50 lines of vanilla JS. Click the toolbar icon → every duplicate tab across every window is removed (matched by URL) → survivors merge into one window → remaining tabs auto-group by hostname (collapsed). Two permissions: tabs, tabGroups. No background activity, no server, no analytics. Whole source is in the README so