ec98ba1230
`.nav-item` was ported from a <button> but the new AppShell renders it as an <a>, and the rule carried every button reset except `text-decoration`. With no global anchor reset, the nav rows (Files, Shared, Recent, …) showed the browser's default link underline. Add `text-decoration: none` to the base rule (covers normal, hover and active states). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>