feat: age verification with an ID document (Didit), and closed registration

Age: a Didit provider behind the vendor-neutral age interface. A person
verifies once (ID document, passive liveness, face match) and all their
linked IMVU accounts count as adult. Webhooks are checked against Didit's
signatures; only "over 18" is kept. A later answer replaces an earlier one
(an approval taken back is revoked). Checks are limited: one unfinished
check per person, 3 in 30 days, none once verified, and a monthly cap
(DIDIT_MONTHLY_LIMIT, default 30: Didit's free plan is $10 of credit a
month and a check costs $0.30). The Account page gets an Age Verification
card.

Registration: open or closed, an admin's setting in the console
(default from REGISTRATION). Closed: new accounts can only sign in until
a moderator approves them (or declines, deleting the account); the
website shows them a waiting page and the API treats them as signed out.

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

apps/web/components/status.tsx

@@ -75,8 +75,8 @@ export function PageHeader({ title, children }: { title: React.ReactNode; childr
 }
 
 /** An IMVU account's age status: blue when it can see adult community products. */
-export function AgeTag({ link }: { link: Pick<Link, "ageVerified" | "accessPass"> }) {
-  if (link.ageVerified) return <Tag tone="adult">Age verified</Tag>;
+export function AgeTag({ link }: { link: Pick<Link, "ageVerified" | "accessPass" | "adult"> }) {
+  if (link.ageVerified || (link.adult && !link.accessPass)) return <Tag tone="adult">Age verified</Tag>;
   if (link.accessPass) return <Tag tone="adult">Access Pass</Tag>;
   return <Tag>Not age verified</Tag>;
 }