feat: self-hosted GitLab Apps OAuth integration

Adds self-hosted GitLab OAuth sources so Coolify can connect to a self-managed GitLab instance, list private repositories, clone over an OAuth token, and deploy (the GitLab counterpart to GitHub Apps).

Hardening: authenticated, one-time team-bound OAuth callback state; token redaction in deploy logs; custom host port/path kept in clone and ls-remote URLs; submodule OAuth auth; system-wide source selection. Covered by unit and feature tests.

cosigned by OpenAI Codex at M1 Max

bootstrap/helpers/github.php

@@ -1,7 +1,6 @@
 <?php
 
 use App\Models\GithubApp;
-use App\Models\GitlabApp;
 use App\Models\PrivateKey;
 use Carbon\Carbon;
 use Carbon\CarbonImmutable;
@@ -216,7 +215,7 @@ function generateGithubJwt(GithubApp $source)
     return generateGithubToken($source, 'jwt');
 }
 
-function githubApi(GithubApp|GitlabApp|null $source, string $endpoint, string $method = 'get', ?array $data = null, bool $throwError = true)
+function githubApi(?GithubApp $source, string $endpoint, string $method = 'get', ?array $data = null, bool $throwError = true)
 {
     if (is_null($source)) {
         throw new Exception('Source is required for API calls');