feat(cms,asset): add comprehensive test suite and finalize modules

- Add comprehensive test suite for CMS and Asset modules using Pest Framework
- Implement ContentTypeService::delete() protection against deletion of in-use content types
- Add CannotDeleteContentTypeInUseException for better error handling
- Fix DerivatPipelineRegistry::getAllPipelines() to handle object uniqueness correctly
- Fix VariantName::getScale() to correctly parse scales with file extensions
- Update CMS module documentation with new features, exceptions, and test coverage
- Add CmsTestHelpers and AssetTestHelpers for test data factories
- Fix BlockTypeRegistry to be immutable after construction
- Update ContentTypeService to check for associated content before deletion
- Improve BlockRendererRegistry initialization

Test coverage:
- Value Objects: All CMS and Asset value objects
- Services: ContentService, ContentTypeService, SlugGenerator, BlockValidator, ContentLocalizationService, AssetService, DeduplicationService, MetadataExtractor
- Repositories: All database repositories with mocked connections
- Rendering: Block renderers and ContentRenderer
- Controllers: API endpoints for both modules

254 tests passing, 38 remaining (mostly image processing pipeline tests)

tests/Unit/Domain/Cms/Services/SlugGeneratorTest.php

@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Domain\Cms\Repositories\ContentRepository;
+use App\Domain\Cms\Services\SlugGenerator;
+use App\Domain\Cms\ValueObjects\ContentSlug;
+
+describe('SlugGenerator', function () {
+    beforeEach(function () {
+        $this->repository = Mockery::mock(ContentRepository::class);
+        $this->slugGenerator = new SlugGenerator($this->repository);
+    });
+
+    it('generates slug from title', function () {
+        $slug = $this->slugGenerator->generateFromTitle('My Awesome Page');
+
+        expect($slug)->toBeInstanceOf(ContentSlug::class);
+        expect($slug->toString())->toBe('my-awesome-page');
+    });
+
+    it('handles special characters in title', function () {
+        $slug = $this->slugGenerator->generateFromTitle('Hello & World!');
+
+        expect($slug->toString())->toBe('hello-world');
+    });
+
+    it('handles empty title', function () {
+        $slug = $this->slugGenerator->generateFromTitle('');
+
+        expect($slug->toString())->toStartWith('content-');
+    });
+
+    it('truncates long titles', function () {
+        $longTitle = str_repeat('a', 300);
+        $slug = $this->slugGenerator->generateFromTitle($longTitle);
+
+        expect(strlen($slug->toString()))->toBeLessThanOrEqual(255);
+    });
+
+    it('generates unique slug when base slug exists', function () {
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page'))
+            ->andReturn(true);
+
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page-1'))
+            ->andReturn(false);
+
+        $slug = $this->slugGenerator->generateUniqueFromTitle('My Page');
+
+        expect($slug->toString())->toBe('my-page-1');
+    });
+
+    it('generates unique slug with multiple collisions', function () {
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page'))
+            ->andReturn(true);
+
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page-1'))
+            ->andReturn(true);
+
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page-2'))
+            ->andReturn(false);
+
+        $slug = $this->slugGenerator->generateUniqueFromTitle('My Page');
+
+        expect($slug->toString())->toBe('my-page-2');
+    });
+
+    it('returns base slug when it does not exist', function () {
+        $this->repository->shouldReceive('existsSlug')
+            ->once()
+            ->with(Mockery::on(fn ($slug) => $slug->toString() === 'my-page'))
+            ->andReturn(false);
+
+        $slug = $this->slugGenerator->generateUniqueFromTitle('My Page');
+
+        expect($slug->toString())->toBe('my-page');
+    });
+});
+