feat(registration): add watcher capacity limits and update pricing

Add 70-person capacity limit for watchers with real-time availability checks.
Update drink card pricing to €5 per person (was €5 base + €2 per guest).
Add feature flag to bypass registration countdown.
Show under-review notice for performer registrations.
Update FAQ performance duration from 5-7 to 5 minutes.

apps/web/src/lib/useRegistrationOpen.ts

@@ -1,5 +1,5 @@
 import { useEffect, useState } from "react";
-import { REGISTRATION_OPENS_AT } from "./opening";
+import { COUNTDOWN_ENABLED, REGISTRATION_OPENS_AT } from "./opening";
 
 interface RegistrationOpenState {
 	isOpen: boolean;
@@ -10,6 +10,9 @@ interface RegistrationOpenState {
 }
 
 function compute(): RegistrationOpenState {
+	if (!COUNTDOWN_ENABLED) {
+		return { isOpen: true, days: 0, hours: 0, minutes: 0, seconds: 0 };
+	}
 	const diff = REGISTRATION_OPENS_AT.getTime() - Date.now();
 	if (diff <= 0) {
 		return { isOpen: true, days: 0, hours: 0, minutes: 0, seconds: 0 };