Feat: improve retrieval API

[Woody-Hu]

What problem does this PR solve?

Get the highlight parameter from the request to keep consistency with the document

• Method: POST
• URL: /api/v1/retrieval
• Headers:
  • 'content-Type: application/json'
  • 'Authorization: Bearer <YOUR_API_KEY>'
• Body:
  • "question": string
  • "dataset_ids": list[string]
  • "document_ids": list[string]
  • "page": integer
  • "page_size": integer
  • "similarity_threshold": float
  • "vector_similarity_weight": float
  • "top_k": integer
  • "rerank_id": string
  • "keyword": boolean
  • "highlight": boolean

Type of change

• [x] Bug Fix (non-breaking change which fixes an issue)
• [x] New Feature (non-breaking change which adds functionality)
• [ ] Documentation Update
• [ ] Refactoring
• [ ] Performance Improvement
• [ ] Other (please describe):