fix(ui): Don't draw a second focus box inside framed text fields

The global focus ring listed input and textarea. :is() takes its most specific
argument, so the rule tied with the components' own :focus-visible resets and won
whenever it loaded later: the Settings search field and the agent composer showed
an inner square box inside their focus frame. Text fields show focus with their
frame; the ring stays on checkboxes, radios and other input controls.

src/styles/global.css

@@ -1,5 +1,3 @@
-@import "@fontsource-variable/inter";
-@import "@fontsource-variable/jetbrains-mono";
 @import "./tokens.css";
 
 /* Monochrome icons default to the theme icon grey; callers override for selected / disabled. */
@@ -95,16 +93,16 @@ a:hover {
 }
 
 /* Focus rings mark controls only, as in IDEA: lists, trees, tables, menus, popups and other
-   focusable containers show focus through their selected row instead of a frame. */
+   focusable containers show focus through their selected row instead of a frame. Text fields
+   aren't listed: their frame shows focus, and an outline here draws a second box inside it. */
 :focus-visible {
   outline: none;
 }
 :is(
   button,
   a[href],
-  input,
+  input:is([type="checkbox"], [type="radio"], [type="range"], [type="color"], [type="file"], [type="button"], [type="submit"], [type="reset"]),
   select,
-  textarea,
   summary,
   [role="button"],
   [role="link"],