debezium/dbz#2128 feat: add Milvus adapter and integration tests

[KMohnishM]

Description

This Pull Request implements the second half of GSoC Week 5 targets under tracking issue debezium/dbz#2128. It introduces support for the Milvus vector database backend and provides integration tests leveraging milvus-lite.

Key Changes

1. Milvus Adapter:
   • Implemented MilvusAdapter in pydebeziumai/adapters/milvus.py extending the core VectorStoreAdapter contract.
   • Utilizes langchain-milvus underneath to perform idempotent upsert, delete, and retriever generation.
   • Handled automatic registration of the PyMilvus connection pool handler via connections.connect dynamically to avoid ORM-layer initialization errors (ConnectionNotExistException).
   • Registered MilvusAdapter in the public adapters interface (pydebeziumai/adapters/__init__.py).
2. Integration Tests:
   • Created a comprehensive integration test suite in tests/integration/test_milvus_adapter.py validating initialization, import errors, upserts, deletes, and retrievals.
   • Configured tests to use isolated, unique temporary database paths (/tmp/m_{uuid}.db) limited to 36 characters to prevent SQLite concurrent file locks and Milvus-Lite database name length limits.

Verification Results

All code validation checks have been successfully run and passed within WSL:

• Ruff Quality Check: Passed (All checks passed!).
• MyPy Type Safety: Passed (Success: no issues found in 36 source files).
• PyTest Execution: 83/83 unit and integration tests passed successfully (including 4 new integration tests for MilvusAdapter).