refactor(gitlab): make GitLabProvider fetch non-blocking

startFetch() resolves the user id and fires the first events page,
returning a handle without reading it; resolveFetch() continues the
existing do/while pagination starting from that first response.

Pagination itself stays sequential within this provider since each
page depends on the previous one - parallelism here only spans across
providers, not within GitLab's own pages.

src/Service/Provider/GitLabProvider.php

@@ -7,6 +7,7 @@ namespace App\Service\Provider;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
 
 /**
  * Fetches the last 365 days of push/merge events from the GitLab REST API.
@@ -46,9 +47,14 @@ final class GitLabProvider implements ProviderInterface
     }
 
     /**
-     * @return array<string, int>  date (Y-m-d) => event count
+     * @return array{baseUrl: string, userId: int, after: string, page: int, response: ResponseInterface}
+     *
+     * ponytail: the user-id lookup and event pagination stay sequential within
+     * this one provider (each page depends on the previous). Parallelism here
+     * only spans across providers; revisit only if GitLab pagination itself
+     * becomes the bottleneck.
      */
-    public function fetch(): array
+    public function startFetch(): array
     {
         $baseUrl = rtrim($this->baseUrl !== '' ? $this->baseUrl : 'https://gitlab.com', '/');
 
@@ -64,21 +70,30 @@ final class GitLabProvider implements ProviderInterface
             throw new NotFoundHttpException("GitLab: user '{$this->username}' not found on $baseUrl");
         }
         $userId = $users[0]['id'];
+        $after  = (new \DateTimeImmutable('-365 days'))->format('Y-m-d');
+
+        $response = $this->client->request('GET', "$baseUrl/api/v4/users/$userId/events", [
+            'headers' => ['PRIVATE-TOKEN' => $this->token],
+            'query'   => [
+                'after'    => $after,
+                'per_page' => 100,
+                'page'     => 1,
+            ],
+        ]);
+
+        return ['baseUrl' => $baseUrl, 'userId' => $userId, 'after' => $after, 'page' => 1, 'response' => $response];
+    }
+
+    /**
+     * @return array<string, int>  date (Y-m-d) => event count
+     */
+    public function resolveFetch(mixed $handle): array
+    {
+        ['baseUrl' => $baseUrl, 'userId' => $userId, 'after' => $after, 'page' => $page, 'response' => $response] = $handle;
 
         $result = [];
-        $after  = (new \DateTimeImmutable('-365 days'))->format('Y-m-d');
-        $page   = 1;
 
         do {
-            $response = $this->client->request('GET', "$baseUrl/api/v4/users/$userId/events", [
-                'headers' => ['PRIVATE-TOKEN' => $this->token],
-                'query'   => [
-                    'after'    => $after,
-                    'per_page' => 100,
-                    'page'     => $page,
-                ],
-            ]);
-
             $events = $response->toArray();
 
             foreach ($events as $event) {
@@ -87,6 +102,17 @@ final class GitLabProvider implements ProviderInterface
             }
 
             $page++;
+
+            if (count($events) === 100) {
+                $response = $this->client->request('GET', "$baseUrl/api/v4/users/$userId/events", [
+                    'headers' => ['PRIVATE-TOKEN' => $this->token],
+                    'query'   => [
+                        'after'    => $after,
+                        'per_page' => 100,
+                        'page'     => $page,
+                    ],
+                ]);
+            }
         } while (count($events) === 100);
 
         $this->logger->info('GitLabProvider: fetched contributions', [