feat(provider): implement ping and probe on GitHub, GitLab, and Gitea

Add getName() and ping() to each provider and wire ProbeTrait. Make
all classes final, add strict_types declarations, and replace generic
RuntimeException with typed HTTP exceptions so probe() can classify
auth failures and unreachable endpoints correctly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Service/GiteaProvider.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Service;
 
 use Psr\Log\LoggerInterface;
@@ -13,8 +15,10 @@ use Symfony\Contracts\HttpClient\HttpClientInterface;
  *
  * Required token scopes: read:user
  */
-class GiteaProvider implements ProviderInterface
+final class GiteaProvider implements ProviderInterface
 {
+    use ProbeTrait;
+
     public function __construct(
         private readonly HttpClientInterface $client,
         private readonly string $username,
@@ -23,17 +27,31 @@ class GiteaProvider implements ProviderInterface
         private readonly LoggerInterface $logger,
     ) {}
 
+    public function getName(): string
+    {
+        return 'gitea';
+    }
+
     public function isConfigured(): bool
     {
         return $this->username !== '' && $this->token !== '' && $this->baseUrl !== '';
     }
 
+    public function ping(): void
+    {
+        $baseUrl = rtrim($this->baseUrl, '/');
+
+        $this->client->request('GET', "$baseUrl/api/v1/user", [
+            'headers' => ['Authorization' => "token {$this->token}"],
+        ])->getContent();
+    }
+
     /**
      * @return array<string, int>  date (Y-m-d) => contribution count
      */
     public function fetch(): array
     {
-        $baseUrl  = rtrim($this->baseUrl, '/');
+        $baseUrl = rtrim($this->baseUrl, '/');
 
         $this->logger->debug('GiteaProvider: fetching contributions', ['user' => $this->username, 'url' => $baseUrl]);