feat(server): improve doc tools error handle (#14662)

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

* **New Features**
* Centralized sync/status messages for cloud document sync and explicit
user-facing error types.
* Frontend helpers to detect and display tool errors with friendly
names.

* **Bug Fixes**
* Consistent, actionable error reporting for document and attachment
reads instead of silent failures.
* Search and semantic tools now validate workspace sync and permissions
and return clear responses.

* **Tests**
* Added comprehensive tests covering document/blob reads, search tools,
and sync/error paths.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/providers/provider.ts

@@ -470,7 +470,8 @@ export abstract class CopilotProvider<C = any> {
               });
               const searchDocs = buildDocKeywordSearchGetter(
                 ac,
-                indexerService
+                indexerService,
+                models
               );
               tools.doc_keyword_search = createDocKeywordSearchTool(
                 searchDocs.bind(null, options)