feat: add vector store configuration properties with migration support

[mayankbohra]

Summary

Implements vector store configuration properties to address issue mem0ai#3447, making vector_store configs as accessible as LLM and Embedder configs.

Changes Made

• Property Accessors: Added direct access to common config fields
  • collection_name, embedding_model_dims, api_key
  • host, port, url, path for connection parameters
• Migration Support: Added methods for UI integration
  • get_migration_config() for database migration operations
  • rebuild_config() for rebuilding vector databases
• API Integration: Added to_dict() for serialization to API responses
• Development Fix: Handle missing package metadata during development

Implementation Details

✅ Enhanced VectorStoreConfig class with property accessors
✅ Added helper methods for migration and rebuild operations
✅ Fixed package import issue in __init__.py
✅ Added comprehensive test suite with 9 test cases
✅ All tests passing (8 passed, 1 skipped)
✅ All linting checks pass with ruff
✅ Pre-commit hooks installed and working
✅ No regression - existing tests continue to pass

Code Example

Before: Nested config access

config = VectorStoreConfig(provider="qdrant", config={"collection_name": "test"})
# Had to access: config.config.collection_name

After: Direct property access

config = VectorStoreConfig(provider="qdrant", config={"collection_name": "test"})
print(config.collection_name)  # Direct access: "test"
print(config.api_key)          # None if not set
print(config.to_dict())        # Serializable dict for API

Testing

pytest tests/configs/test_vector_store_config.py -v
# Result: 8 passed, 1 skipped, 1 warning

Files Changed

• mem0/vector_stores/configs.py - Enhanced VectorStoreConfig class
• mem0/__init__.py - Fixed package import for development
• tests/configs/test_vector_store_config.py - Comprehensive test suite

Closes mem0ai#3447

[mayankbohra]

Closing this PR as it was created on the wrong repository. The correct PR has been created on the upstream repository at mem0ai#3498