fix(ui): simplify GitLab source setup view

Use the red incomplete-setup alert like GitHub, keep name + OAuth
credentials front-and-center, and tuck GitLab URL / API / SSH / system
wide options into an Advanced accordion for self-hosted users.

tests/Feature/GitlabSourceChangeViewTest.php

@@ -0,0 +1,59 @@
+<?php
+
+use App\Livewire\Source\Gitlab\Change;
+use App\Models\GitlabApp;
+use App\Models\InstanceSettings;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    $this->team = Team::factory()->create();
+    $this->user = User::factory()->create();
+    $this->team->members()->attach($this->user->id, ['role' => 'owner']);
+
+    $this->actingAs($this->user);
+    session(['currentTeam' => $this->team]);
+
+    InstanceSettings::forceCreate([
+        'id' => 0,
+        'fqdn' => null,
+        'public_ipv4' => null,
+        'public_ipv6' => null,
+    ]);
+
+    $this->gitlabApp = GitlabApp::create([
+        'name' => 'Self-hosted GitLab',
+        'api_url' => 'https://gitlab.com/api/v4',
+        'html_url' => 'https://gitlab.com',
+        'custom_user' => 'git',
+        'custom_port' => 22,
+        'team_id' => $this->team->id,
+        'is_system_wide' => false,
+        'is_public' => false,
+    ]);
+});
+
+describe('GitLab source setup view', function () {
+    test('shows red incomplete-setup alert and keeps advanced fields collapsed', function () {
+        Livewire::withQueryParams(['gitlab_app_uuid' => $this->gitlabApp->uuid])
+            ->test(Change::class)
+            ->assertSee('You must complete this step before you can use this source!')
+            ->assertSeeHtml('alert-error')
+            ->assertSee('Advanced / Self-hosted')
+            ->assertSee('Application ID')
+            ->assertSee('Application Secret')
+            ->assertSee('Save Credentials')
+            ->assertDontSee('alert-warning');
+    });
+
+    test('derives api url when gitlab url changes', function () {
+        Livewire::withQueryParams(['gitlab_app_uuid' => $this->gitlabApp->uuid])
+            ->test(Change::class)
+            ->set('htmlUrl', 'https://gitlab.example.com')
+            ->assertSet('apiUrl', 'https://gitlab.example.com/api/v4');
+    });
+});