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/api/src/index.ts

@@ -4,9 +4,19 @@
 //   API_URL          the API's address as the website and proxies reach it (default http://localhost:4101)
 //   WEB_URL          the website's address (default http://localhost:4100)
 //   PORT             default 4101
+//   REGISTRATION     open or closed (new accounts wait for a moderator's approval), until an admin sets it in the console
+//   AGE_PROVIDERS    ways to verify age, comma-separated (default imvu): imvu, didit
+//   DIDIT_API_KEY, DIDIT_WORKFLOW_ID, DIDIT_WEBHOOK_SECRET
+//                    Didit's ID document check (docs/design.md, "Age"); its webhook is API_URL/api/v1/age/webhook/didit
+//   DIDIT_MONTHLY_LIMIT  checks started a month at most (default 30: Didit's free plan has $10 of credit a month, and a
+//                    check with ID document, liveness and face match costs $0.30)
 import { openDatabase } from "@t5de/db";
+import { AgeService, type Provider } from "./age";
+import { diditAgeProvider } from "./age/didit";
+import { imvuAgeProvider } from "./age/imvu";
 import { createApp } from "./app";
 import { createAuth } from "./auth";
+import { Settings } from "./settings";
 import { ImvuClient } from "./imvu";
 
 const env = process.env;
@@ -21,8 +31,39 @@ const apiURL = env.API_URL ?? `http://localhost:${port}`;
 const webURL = env.WEB_URL ?? "http://localhost:4100";
 
 const { db } = await openDatabase(env.DATABASE_URL ?? "./data/db");
-const auth = createAuth(db, { apiURL, webURL, secret });
-const { app, age, rooms, products } = createApp({ db, auth, imvu: new ImvuClient(), apiURL });
+const settings = new Settings(db, { registration: env.REGISTRATION });
+const auth = createAuth(db, { apiURL, webURL, secret, settings });
+const imvu = new ImvuClient();
+
+function required(name: string): string {
+  const v = env[name];
+  if (!v) {
+    console.error(`${name} must be set`);
+    process.exit(1);
+  }
+  return v;
+}
+const ageProviders: Record<string, () => Provider> = {
+  imvu: () => imvuAgeProvider(imvu),
+  didit: () =>
+    diditAgeProvider({
+      apiKey: required("DIDIT_API_KEY"),
+      workflowId: required("DIDIT_WORKFLOW_ID"),
+      webhookSecret: required("DIDIT_WEBHOOK_SECRET"),
+      monthlyLimit: Number(env.DIDIT_MONTHLY_LIMIT ?? 30),
+    }),
+};
+const providers = (env.AGE_PROVIDERS ?? "imvu").split(",").map((id) => id.trim()).filter(Boolean);
+if (!providers.includes("imvu")) providers.unshift("imvu"); // linking records IMVU's answer
+for (const id of providers) {
+  if (!ageProviders[id]) {
+    console.error(`AGE_PROVIDERS: no provider ${id}`);
+    process.exit(1);
+  }
+}
+const ageService = new AgeService(db, providers.map((id) => ageProviders[id]!()));
+
+const { app, age, rooms, products } = createApp({ db, auth, imvu, age: ageService, apiURL, webURL, settings });
 app.listen({ port, hostname: env.HOST ?? "0.0.0.0" });
 
 // Age answers that can change (IMVU's) are checked again when they expire, a few at a time; revisions missing their