Clean implementation that adds support for multiple parameters in query_param and document_param using key=value format.

✅ Based on merged PR #702 - This enhancement builds on the merged is_query parameter API from main branch.

Changes

• Add _parse_param_string() method for key=value parsing
• Enhance _build_extra_body() to support multiple parameters with the is_query flag
• Update docstrings and examples to show new API
• Maintain full backward compatibility

API Integration

• Uses is_query parameter from the embed() method signature (now merged in main)
• Clean enhancement of existing _build_extra_body() method
• No breaking changes - all existing usage continues to work

Usage Examples

Simple Format (Backward Compatible)

embedder = OpenAIDenseEmbedder(
    query_param='query',
    document_param='passage'
)

# Query embedding
result = embedder.embed('search text', is_query=True)
# → extra_body: {'input_type': 'query'}

# Document embedding  
result = embedder.embed('document text', is_query=False)
# → extra_body: {'input_type': 'passage'}

Enhanced Format (Multiple Parameters)

embedder = OpenAIDenseEmbedder(
    query_param='input_type=query,task=search,domain=finance',
    document_param='input_type=passage,task=index,domain=finance'
)

# Query embedding with multiple parameters
result = embedder.embed('financial query', is_query=True)
# → extra_body: {'input_type': 'query', 'task': 'search', 'domain': 'finance'}

# Document embedding with multiple parameters
result = embedder.embed('financial document', is_query=False)
# → extra_body: {'input_type': 'passage', 'task': 'index', 'domain': 'finance'}

Benefits

• Clean integration with merged PR feat(embedding): combine document embedder and query embedder to avoi… #702's is_query API
• Multiple parameter support beyond just input_type
• Future-proof for advanced OpenAI-compatible servers
• Backward compatible with existing simple string format
• No new dependencies or breaking changes

Testing

All functionality tested with both simple and enhanced parameter formats. Ready for review! 🚀