fix(server): query workspace embed files (#11982)

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

- **New Features**
	- Expanded file chunk matching to include both context and workspace file embeddings, providing broader and more relevant search results.
- **Improvements**
	- Enhanced result ranking by introducing a re-ranking step for combined embedding matches, improving the relevance of returned file chunks.
	- Adjusted file count reporting to reflect the total number of workspace files instead of ignored documents for more accurate workspace file statistics.
	- Renamed and streamlined workspace file management methods for clearer and more consistent API usage.
- **Bug Fixes**
	- Prevented embedding similarity queries when embedding is disabled for a workspace, improving system behavior consistency.
- **Tests**
	- Added comprehensive tests to verify workspace embedding management, including enabling, matching, and disabling embedding functionality.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/models/copilot-context.ts

@@ -153,7 +153,7 @@ export class CopilotContextModel extends BaseModel {
     return Prisma.join(groups.map(row => Prisma.sql`(${Prisma.join(row)})`));
   }
 
-  async insertContentEmbedding(
+  async insertFileEmbedding(
     contextId: string,
     fileId: string,
     embeddings: Embedding[]
@@ -168,7 +168,7 @@ export class CopilotContextModel extends BaseModel {
   `;
   }
 
-  async matchContentEmbedding(
+  async matchFileEmbedding(
     embedding: number[],
     contextId: string,
     topK: number,