feat(database): default new Redis databases to the Valkey image

Change the standalone_redis image column default to
valkey/valkey:9-alpine. Existing databases keep their current image.
Update the API docs, OpenAPI specs and image helper text to name Valkey
as the default and redis:8 as the Redis example.

Also restyle the status badges and database image cards on the new
resource page.

app/Http/Controllers/Api/DatabasesController.php

@@ -1731,7 +1731,7 @@ class DatabasesController extends Controller
 
     #[OA\Post(
         summary: 'Create (Redis / Valkey)',
-        description: 'Create a new Redis or Valkey database. Set image to a Valkey image (for example valkey/valkey:9-alpine) for Valkey.',
+        description: 'Create a new Redis or Valkey database. Valkey (valkey/valkey:9-alpine) is the default. Set image to a Redis image (for example redis:8) for Redis.',
         path: '/databases/redis',
         operationId: 'create-database-redis',
         security: [
@@ -1757,7 +1757,7 @@ class DatabasesController extends Controller
                         'redis_conf' => ['type' => 'string', 'description' => 'Redis conf'],
                         'name' => ['type' => 'string', 'description' => 'Name of the database'],
                         'description' => ['type' => 'string', 'description' => 'Description of the database'],
-                        'image' => ['type' => 'string', 'description' => 'Docker image of the database. Default: redis:7.2. For Valkey, use a Valkey image, for example valkey/valkey:9-alpine.'],
+                        'image' => ['type' => 'string', 'description' => 'Docker image of the database. Default: valkey/valkey:9-alpine. For Redis, use a Redis image, for example redis:8.'],
                         'is_public' => ['type' => 'boolean', 'description' => 'Is the database public?'],
                         'public_port' => ['type' => 'integer', 'description' => 'Public port of the database'],
                         'public_port_timeout' => ['type' => 'integer', 'description' => 'Public port timeout in seconds (default: 3600)'],