feat(preview): expose availability and handle missing services

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

tests/php/Unit/Preview/PreviewManagerTest.php

@@ -154,12 +154,7 @@ final class PreviewManagerTest extends TestCase
         $service = $this->createMock(SystemStoreServiceInterface::class);
         $service->expects(self::once())->method('stat')->willReturn(null);
         $logger = $this->createMock(LoggerInterface::class);
-        $logger->expects(self::once())->method('warning')->with(
-            'Preview unavailable',
-            self::callback(static fn(array $context): bool =>
-                ($context['exception'] ?? null) instanceof PreviewGenerationException
-            ),
-        );
+        $logger->expects(self::never())->method('warning');
 
         self::assertNull($this->manager(
             $provider,
@@ -169,6 +164,50 @@ final class PreviewManagerTest extends TestCase
         )->fetch('tenant-a', $this->source()));
     }
 
+    #[Test]
+    public function missingPreviewStorageIsUnavailableWithoutLoggingOrProviderLookup(): void
+    {
+        $provider = $this->provider();
+        $provider->expects(self::never())->method('generate');
+        $providerManager = $this->createMock(ProviderManager::class);
+        $providerManager->expects(self::never())->method('providers');
+        $service = $this->createMock(SystemStoreServiceInterface::class);
+        $service->expects(self::never())->method('stat');
+        $logger = $this->createMock(LoggerInterface::class);
+        $logger->expects(self::never())->method('warning');
+
+        self::assertNull($this->manager(
+            $provider,
+            $service,
+            new TenantConfiguration(),
+            $providerManager,
+            $logger,
+        )->fetch('tenant-a', $this->source()));
+    }
+
+    #[Test]
+    public function reportsStorageAndGenerationAvailabilitySeparately(): void
+    {
+        $provider = $this->provider();
+        $providerManager = $this->createMock(ProviderManager::class);
+        $providerManager->expects(self::once())->method('providers')->willReturn([]);
+        $logger = $this->createMock(LoggerInterface::class);
+        $logger->expects(self::once())->method('debug')->with(
+            'No preview generation provider is available',
+            ['tenantId' => 'tenant-a'],
+        );
+
+        self::assertSame(
+            ['enabled' => true, 'storage' => true, 'generation' => false],
+            $this->manager(
+                $provider,
+                $this->createStub(SystemStoreServiceInterface::class),
+                providerManager: $providerManager,
+                logger: $logger,
+            )->availability('tenant-a'),
+        );
+    }
+
     #[Test]
     public function cacheKeysAreDeterministicOpaqueAndChangeWithSourceIdentity(): void
     {