style(desktop): kill focus rings globally

Tab/focus showed Tailwind's `focus-visible:ring-*` (a box-shadow) plus the
native outline. Drop both via an unlayered reset that nulls --tw-ring-*;
the composer / input soft-glow is untouched (those use direct box-shadows).

apps/desktop/src/styles.css

@@ -568,6 +568,21 @@
   }
 }
 
+/* No focus rings, anywhere. Kills the native outline plus Tailwind's
+   `focus-visible:ring-*` (a box-shadow driven by --tw-ring-*). Unlayered so it
+   beats the utilities layer without !important on the outline. The composer /
+   .desktop-input-chrome focus glow is untouched — those set `box-shadow`
+   directly rather than through the ring vars. */
+*:focus,
+*:focus-visible {
+  outline: none;
+}
+
+*:focus-visible {
+  --tw-ring-shadow: 0 0 #0000 !important;
+  --tw-ring-offset-shadow: 0 0 #0000 !important;
+}
+
 button {
   -webkit-app-region: no-drag;
 }