fix(server): config & update handle (#15173)

#### PR Dependency Tree


* **PR #15173** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added native document update validation to check incoming Yjs updates
for decodability before applying them.
* Introduced support for validation timeouts and cancellation during
update checks.
* Blob maintenance jobs now detect when object storage is unavailable
and skip related work gracefully.

* **Bug Fixes**
* Invalid (and oversized) updates are now filtered out earlier during
document ingestion.
* Background blob maintenance continues processing other work even if
one workspace fails.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/native/index.d.ts

@@ -514,6 +514,12 @@ export declare function llmValidateJsonSchema(schema: any, value: any): any
  */
 export declare function mergeUpdatesInApplyWay(updates: Array<Buffer>): Buffer
 
+/**
+ * Check whether a Yjs update binary can be decoded without applying it to a
+ * document state.
+ */
+export declare function validateDocUpdate(update: Buffer): Promise<boolean>
+
 export declare function mintChallengeResponse(resource: string, bits?: number | undefined | null): Promise<string>
 
 export interface ModelConditionsContract {