Add generación y expiración de tokens de sesión

mvp/b2c/src/lib/auth/tokens.ts

@@ -0,0 +1,19 @@
+import { randomBytes, createHash } from 'node:crypto';
+
+export const SESSION_TTL_MS = 30 * 24 * 60 * 60 * 1000; // 30 días
+
+export function generateSessionToken(): string {
+  return randomBytes(32).toString('hex');
+}
+
+export function hashSessionToken(token: string): string {
+  return createHash('sha256').update(token).digest('hex');
+}
+
+export function isSessionExpired(expiresAt: Date, now: Date = new Date()): boolean {
+  return expiresAt.getTime() <= now.getTime();
+}
+
+export function sessionExpiry(now: Date = new Date()): Date {
+  return new Date(now.getTime() + SESSION_TTL_MS);
+}