fix(nav): wrap header links on narrow viewports

The six-item header stayed on one nowrap flex row, so a 390px viewport
expanded to ~510px (Projects at 436px, Wiki at 510px). Allow wrapping
and keep each link intact so mobile pages no longer scroll sideways.

Git-Session-Id: 903e

Author: TimeToBuildBob

assets/css/tailwind.css

@@ -48,10 +48,11 @@
     @apply bg-surface border-b border-border shadow-sm;
 
     nav {
-      @apply container mx-auto px-4 py-4 flex gap-6;
+      /* Wrap: six nowrap links overflow a 390px viewport to ~510px. */
+      @apply container mx-auto px-4 py-4 flex flex-wrap items-center gap-x-4 gap-y-2 sm:gap-6;
 
       a {
-        @apply text-text no-underline px-2 py-1 hover:text-primary transition-colors;
+        @apply text-text no-underline px-2 py-1 hover:text-primary transition-colors whitespace-nowrap;
       }
     }
   }