feat: deploy AmneziaWG instances from the panel (no Amnezia app)

Add a "Протоколы / инстансы" section that spins up AmneziaWG server
containers straight from the panel, with port + variant selection —
no need to run the Amnezia desktop app to set up the server.

Core (scripts/awg-instance.sh):
- create <awg2|awg|legacy> <port> [name]: pulls the public image
  (amneziavpn/amneziawg-go:2.0.0 / :0.2.18 / amneziavpn/amnezia-wg),
  generates server keys + psk, writes awg0.conf/wg0.conf with a free
  10.8.<N>.0/24 subnet (scans running containers to avoid clashes),
  random AmneziaWG obfuscation (Jc/Jmin/Jmax/S1..S4/H1..H4 as single
  uint32 values — ranges break awg setconf), and a start.sh that
  brings the iface up via userspace amneziawg-go + NAT MASQUERADE.
  remove <name>, list.

Backend (server.js):
- Profiles are now dynamic: env AWG_PROFILES merged with managed
  instances persisted in /data/instances.json (getProfiles()), so a
  new instance is usable immediately without restarting the panel.
- /api/instances (list with running/peers), /api/instances/create,
  /delete, /stop, /start. create runs the script then registers the
  profile; delete tears down container + data + profile.

Infra:
- Dockerfile: add bash iproute2 coreutils, COPY scripts.
- install.sh: mkdir /opt/amnezia-instances and bind-mount it into the
  panel so docker-in-docker bind paths line up.

UI (index.html/app.js/styles.css):
- Cards per instance (icon, NEW badge, description, РАБОТАЕТ/ОСТАНОВЛЕН,
  port, connections) with Стоп/Старт, Подключения (switches the active
  instance), Удалить; plus a create form (variant + port).

Verified end to end on a live VPS: create awg2/awg/legacy instances,
interfaces come up, a client created on a new instance gets the right
subnet (10.8.20.2) and Endpoint (host:51850).

public/index.html

@@ -183,6 +183,35 @@
       </div>
     </details>
 
+    <details class="panel-fold" id="instances-panel" open>
+      <summary class="fold-summary">
+        <span class="fold-arrow" aria-hidden="true"></span>
+        <span class="fold-titles">
+          <span class="fold-h">Протоколы / инстансы</span>
+          <span class="muted fold-meta">Разверните AmneziaWG прямо из панели — без приложения Amnezia, с выбором порта</span>
+        </span>
+      </summary>
+      <div class="panel-fold-body">
+        <div id="instances-grid" class="instances-grid"></div>
+        <form id="instance-form" class="instance-form">
+          <div class="instance-form-row">
+            <label for="instance-variant">Протокол</label>
+            <select id="instance-variant" class="form-select">
+              <option value="awg2">AmneziaWG 2.0 (рекомендуется)</option>
+              <option value="awg">AmneziaWG</option>
+              <option value="legacy">AmneziaWG Legacy</option>
+            </select>
+          </div>
+          <div class="instance-form-row">
+            <label for="instance-port">Порт (UDP)</label>
+            <input id="instance-port" type="number" min="1" max="65535" placeholder="напр. 51820" autocomplete="off">
+          </div>
+          <button type="submit" class="btn primary">＋ Развернуть инстанс</button>
+        </form>
+        <p class="muted instance-hint">Создаёт серверный контейнер AmneziaWG из публичного образа, генерирует ключи и NAT. Затем в «Пользователях» выберите инстанс и создавайте клиентов.</p>
+      </div>
+    </details>
+
     <details class="panel-fold" id="direct-panel" open>
       <summary class="fold-summary">
         <span class="fold-arrow" aria-hidden="true"></span>