fix(ui): make input borders visible in dark mode

The dark-mode --input value (oklch 0.269) sat almost on top of the
background (0.225), making the shared border-input nearly invisible on
every input, checkbox, radio, select and textarea. Bump it to 0.41 so
the borders read clearly while staying below the focus ring (0.439).

resources/css/app.css

@@ -134,7 +134,7 @@
     --destructive: oklch(0.396 0.141 25.723);
     --destructive-foreground: oklch(0.637 0.237 25.331);
     --border: oklch(0.325 0 0);
-    --input: oklch(0.269 0 0);
+    --input: oklch(0.41 0 0);
     --ring: oklch(0.439 0 0);
     --chart-1: var(--color-zinc-200);
     --chart-2: var(--color-zinc-300);