Admin Payments: one 'Ways to pay' group of switches; provider credentials are Billing's environment, never Live settings (Live#303 removes them) (#302)

ddiff --git a/public/js/admin/payments.js b/public/js/admin/payments.js
iindex b98ba991..70b47fe1 100644
---- a/public/js/admin/payments.js
++++ b/public/js/admin/payments.js
@@@ -6,14 +6,13 @@
     ═══════════════════════════════════════════════════════════════ */
  // ── Payments: the switches and prices OpenVibe.Live reads ──
  // OpenVibe.Billing runs every checkout, webhook, subscription and cashout since the cutover of 2026-10-17. Live
--// still reads these site settings to decide which ways to pay it offers and at what price (Live's
--// server/monetization/payments.js). Provider credentials are Billing's environment variables, never settings here.
++// reads these site settings to decide which ways to pay it offers and at what price (Live's
++// server/monetization/payments.js): a provider is offered when payments_enabled and its own switch are on and Billing
++// reports it enabled (Billing holds its keys). Provider credentials are Billing's environment variables, never
++// settings here (Live#303 removed the old credential settings).
  const PAYMENT_GROUPS = [
      { title: 'General', keys: ['payments_enabled', 'bucks_per_usd', 'bucks_min_purchase_bucks', 'sub_price_usd', 'sub_streamer_share_pct', 'sub_site_route_fee_pct'] },
--    { title: 'PayPal', keys: ['paypal_enabled', 'paypal_client_id'] },
--    { title: 'Stripe', keys: ['stripe_enabled', 'stripe_secret_key', 'stripe_publishable_key'] },
--    { title: 'CCBill', keys: ['ccbill_enabled', 'ccbill_flexform_id'] },
--    { title: 'Crypto (NOWPayments)', keys: ['crypto_enabled', 'crypto_api_key'] },
++    { title: 'Ways to pay', keys: ['stripe_enabled', 'paypal_enabled', 'ccbill_enabled', 'crypto_enabled'] },
  ];
  // Where providers send payments (OpenVibe.Billing server/api/webhooks.js) and the variables Billing reads
  // (its server/config.js), set in /etc/openvibe/billing.env on the host.
@@@ -75,7 +74,7 @@ async function loadPayments() {
              </fieldset>`).join('');
          c.innerHTML = `
              <div style="max-width:860px">
--                <p class="muted" style="margin-bottom:12px">OpenVibe.Billing runs every checkout, subscription and cashout. These are the switches and prices OpenVibe.Live reads to decide which ways to pay it offers: nothing is offered until <strong>payments_enabled</strong> and the provider are on. Live also checks that <strong>stripe_secret_key</strong> and <strong>crypto_api_key</strong> are filled in before it offers Stripe or crypto; the keys Billing charges with are in its environment (below).</p>
++                <p class="muted" style="margin-bottom:12px">OpenVibe.Billing runs every checkout, subscription and cashout. These are the switches and prices OpenVibe.Live reads to decide which ways to pay it offers. A way to pay is offered when <strong>payments_enabled</strong> and its own switch are on and Billing has that provider's keys in its environment (below); with no keys there, the switch has no effect.</p>
                  <form id="payments-form">${groups}
                      <button type="button" class="btn btn-primary" onclick="savePayments()"><i class="fa-solid fa-floppy-disk" aria-hidden="true"></i> Save payment settings</button>
                  </form>
ddiff --git a/test/admin-service-proxies.test.js b/test/admin-service-proxies.test.js
iindex 179f54da..67432774 100644
---- a/test/admin-service-proxies.test.js
++++ b/test/admin-service-proxies.test.js
@@@ -132,7 +132,8 @@ function upstream(name) {
          assert.ok(!panel.includes(gone), `the admin panel no longer uses ${gone}`);
      }
      const payments = read('js/admin/payments.js');
--    for (const key of ['paypal_client_secret', 'paypal_webhook_id', 'stripe_webhook_secret', 'ccbill_salt', 'ccbill_webhook_secret', 'crypto_ipn_secret']) {
++    for (const key of ['paypal_client_secret', 'paypal_webhook_id', 'stripe_webhook_secret', 'ccbill_salt', 'ccbill_webhook_secret', 'crypto_ipn_secret',
++        'paypal_client_id', 'stripe_secret_key', 'stripe_publishable_key', 'ccbill_flexform_id', 'crypto_api_key']) {
          assert.ok(!payments.includes(`'${key}'`), `the Payments form no longer saves ${key} into Live's settings (Billing reads its environment)`);
      }
      for (const hook of ['stripe', 'paypal', 'ccbill', 'nowpayments', 'powerchat']) assert.ok(payments.includes(`'/webhooks/${hook}`), `Billing's ${hook} webhook is shown`);