Removing #rightrail left a dead 360px grid column that narrowed #main. Shell grid is now sidebar+main; the topbar ◆ (was Toggle-companion-rail) now dispatches dross-toggle to open/close the floating bubble. Remaining .rail-* CSS + chrome.js toggleRail are dead no-ops (minor cleanup later). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>