copy(waitlist): drop "no spam, unsubscribe anytime" from demo + marketing

Trim the waitlist microcopy on the standalone demo and the marketing site's
CTA/hero forms to just the value prop, removing the "no spam, unsubscribe
anytime" reassurance line.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01REwWZGkAz1AZUJw8yqxkCN

web/standalone/src/components/WaitlistForm.tsx

@@ -47,8 +47,7 @@ export function WaitlistForm({ source = "standalone" }: { source?: string }) {
       ) : (
         <>
           <p className="mb-4 text-sm text-muted-foreground">
-            Join the waitlist for product updates and your invite — no spam,
-            unsubscribe anytime.
+            Join the waitlist for product updates and your invite.
           </p>
           <form onSubmit={submit} className="flex flex-col gap-2 sm:flex-row">
             <Input