fix(awg2): resolve issue #50 client key generation and install timeout

Issue #50 (AmneziaWG 2.0 / awg2): "Failed to generate client keys" when
creating clients, and "Invalid server response" on first install.

- VpnClient::generateClientKeys() built its own password-only SSH command
  (PubkeyAuthentication=no, no sudo), bypassing VpnServer::executeCommand.
  That broke key-based servers and hosts where docker requires sudo. Route
  it through executeCommand so SSH-key auth and docker sudo auto-detection
  apply, matching every other remote operation.
- VpnClient::getNextClientIP() read /opt/amnezia/awg/wg0.conf only; AWG2
  uses awg0.conf. Read awg0.conf first, fall back to wg0.conf.
- deploy route: lift PHP time limit (set_time_limit(0) + ignore_user_abort)
  so the multi-minute awg2 docker build is not killed mid-request, which
  produced the truncated, non-JSON "Invalid server response".
- migration 070: drop `--no-cache` from the awg2 docker build so layers are
  reused, making installs and retries fast and idempotent.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

public/index.php

@@ -568,6 +568,13 @@ Router::post('/servers/{id}/deploy', function ($params) {
     requireAuth();
     header('Content-Type: application/json');
 
+    // Some protocols (e.g. AmneziaWG 2.0 / awg2) build a Docker image from source
+    // on the remote host, which can take several minutes. Without lifting the PHP
+    // time limit the request is killed mid-build and the browser receives a
+    // truncated, non-JSON body shown as "Invalid server response" (issue #50).
+    @set_time_limit(0);
+    @ignore_user_abort(true);
+
     $serverId = (int) $params['id'];
     $rawBody = file_get_contents('php://input');
     $options = [];