fix: disable default view transition crossfade on page content

Only named elements (header, logo, etc.) should animate during
navigation; the root crossfade caused a flash on every page change.

src/app.css

@@ -386,6 +386,17 @@ a:focus-visible {
 	color: var(--color-text-on-primary);
 }
 
+/* ============================================
+   VIEW TRANSITIONS
+   Disable default crossfade on page content;
+   only named elements (header, logo, etc.) animate.
+   ============================================ */
+
+::view-transition-old(root),
+::view-transition-new(root) {
+	animation: none;
+}
+
 /* ============================================
    RECIPE GRID
    Responsive card grid used across recipe pages