feat: redesign UI and UX around design-engineering principles

- Ink-first palette, drop gradients/glow; tabular numbers
- Home: form stays put, results stack below and auto-copy; paste shortens instantly
- Hold-to-delete replaces the delete confirm modal
- Copy buttons morph to a check instead of toasting
- Motion: CSS press feedback, custom ease-out, origin-aware menu, faster exits,
  no animation on frequent/keyboard actions, reduced-motion respected
- Fix: scheme-less URLs ("example.com") were blocked by native validation

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/components/Logo.tsx

@@ -8,10 +8,10 @@ export function Logo({ onClick }: { onClick?: () => void }) {
       onClick={onClick}
       className="focusable inline-flex items-center gap-2 rounded-lg"
     >
-      <span className="grad-bg grid h-7 w-7 place-items-center rounded-lg">
+      <span className="grid h-7 w-7 place-items-center rounded-lg bg-[var(--ink)] text-[var(--bg)]">
         <Scissors size={15} />
       </span>
-      <span className="text-[17px] font-semibold tracking-tight text-ink">
+      <span className="text-[16px] font-semibold tracking-[-0.02em] text-ink">
         snip
       </span>
     </Link>