feat(deployments): support Docker image tags for preview deployments

Add end-to-end support for `docker_registry_image_tag` in preview and deployment queue flows.

- Extend deploy API to accept `pull_request_id` alias and `docker_tag` for preview deploys
- Persist preview-specific Docker tags on `application_previews` and `application_deployment_queues`
- Pass tag through `queue_application_deployment()` and de-duplicate queued jobs by tag
- Update deployment job logic to resolve and use preview Docker tags for dockerimage build packs
- Update Livewire previews UI/state to manage per-preview tags and manual preview/tag inputs
- Add migration for new tag columns and model fillable/casts updates
- Add feature and unit tests covering API behavior and tag resolution

app/Models/DockerCleanupExecution.php

@@ -7,6 +7,7 @@ use Illuminate\Database\Eloquent\Relations\BelongsTo;
 class DockerCleanupExecution extends BaseModel
 {
     protected $fillable = [
+        'server_id',
         'status',
         'message',
         'cleanup_log',