feat(server): add cloud indexer with Elasticsearch and Manticoresearch providers (#11835)

close CLOUD-137

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

- **New Features**
  - Introduced advanced workspace-scoped search and aggregation capabilities with support for complex queries, highlights, and pagination.
  - Added pluggable search providers: Elasticsearch and Manticoresearch.
  - New GraphQL queries, schema types, and resolver support for search and aggregation.
  - Enhanced configuration options for search providers in self-hosted and cloud deployments.
  - Added Docker Compose services and environment variables for Elasticsearch and Manticoresearch.
  - Integrated indexer service into deployment and CI workflows.

- **Bug Fixes**
  - Improved error handling with new user-friendly error messages for search provider and indexer issues.

- **Documentation**
  - Updated configuration examples and environment variable references for indexer and search providers.

- **Tests**
  - Added extensive end-to-end and provider-specific tests covering indexing, searching, aggregation, deletion, and error cases.
  - Included snapshot tests and test fixtures for search providers.

- **Chores**
  - Updated deployment scripts, Helm charts, and Kubernetes manifests to include indexer-related environment variables and secrets.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/base/error/def.ts

@@ -861,4 +861,21 @@ export const USER_FRIENDLY_ERRORS = {
     type: 'invalid_input',
     message: 'Invalid app config.',
   },
+
+  // indexer errors
+  search_provider_not_found: {
+    type: 'resource_not_found',
+    message: 'Search provider not found.',
+  },
+  invalid_search_provider_request: {
+    type: 'invalid_input',
+    args: { reason: 'string', type: 'string' },
+    message: ({ reason }) =>
+      `Invalid request argument to search provider: ${reason}`,
+  },
+  invalid_indexer_input: {
+    type: 'invalid_input',
+    args: { reason: 'string' },
+    message: ({ reason }) => `Invalid indexer input: ${reason}`,
+  },
 } satisfies Record<string, UserFriendlyErrorOptions>;