feat: seed default plugins/pipelines, auto-enqueue jobs on asset ingest

- Migration seeds metadata_extractor, sidecar_sync, no_op plugins
- Pipelines: extract_metadata → metadata_extractor, sync_sidecar → sidecar_sync
- Worker reacts to AssetIngested → enqueues ExtractMetadata job
- Worker reacts to SidecarSyncRequested → enqueues SyncSidecar job
- Closes the ingest-to-processing loop end-to-end

crates/domain/src/common/ports.rs

@@ -16,5 +16,8 @@ pub trait EventConsumer: Send + Sync {
 #[async_trait]
 pub trait EventStore: Send + Sync {
     async fn append(&self, event: &DomainEvent) -> Result<(), DomainError>;
-    async fn query_by_aggregate(&self, aggregate_id: &SystemId) -> Result<Vec<DomainEvent>, DomainError>;
+    async fn query_by_aggregate(
+        &self,
+        aggregate_id: &SystemId,
+    ) -> Result<Vec<DomainEvent>, DomainError>;
 }