feat(site): consistent card radius and remove duplicate login CTAs

Professional tidy-up of the landing experience:
- SurfaceCard: unified rounded-xl radius for a crisper, consistent look.
- Hero: matches the new card radius and gains a dual-direction title
  shadow so the headline stays readable over the header artwork.
- Login/register: drop the duplicated "no account / have an account"
  paragraphs — the forms already ship an inline footer, so one clear CTA
  cluster remains and the side column is cleaner.

src/app/(site)/page.tsx

@@ -214,7 +214,7 @@ export default async function Home() {
 			{/* ── Hero ── */}
 			<Reveal>
 				<div
-					className="relative overflow-hidden rounded-2xl sm:rounded-3xl border"
+					className="relative overflow-hidden rounded-xl border"
 					style={{
 						borderColor:
 							"color-mix(in srgb, var(--color-text-muted) 8%, transparent)",
@@ -270,6 +270,8 @@ export default async function Home() {
 							className="text-2xl font-black leading-[1.05] tracking-tight mb-2 sm:text-3xl md:text-5xl lg:text-6xl"
 							style={{
 								fontFamily: "var(--font-nunito)",
+								textShadow:
+									"0 1px 0 color-mix(in srgb, #ffffff 35%, transparent), 0 2px 14px color-mix(in srgb, #000 28%, transparent)",
 							}}
 						>
 							<span style={{ color: "var(--color-text-readable)" }}>