add langchain standard integration test

[euphoria0-0]

LangChain standard integration test 를 추가합니다.
standard test의 output에 맞춰서 vector store output도 수정하였습니다.

ENVECTOR_ADDRESS="localhost:50050" ENVECTOR_KEY_PATH="./keys" ENVECTOR_KEY_ID="test_key" ENVECTOR_INDEX_NAME="test_index" python -m pytest -q -rs

[Copilot]

Pull request overview

This PR adds LangChain standard integration tests to verify the Envector vector store implementation conforms to LangChain's test suite. The changes introduce a new integration test file that leverages LangChain's VectorStoreIntegrationTests base class and adds a unit test to verify document ID handling behavior.

Key changes:

• Adds LangChain standard integration test class that runs against a live Envector instance
• Adds unit test for document ID handling to ensure IDs are ignored and item IDs are returned
• Updates dependencies to include langchain-core and langchain-tests packages

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/test_vectorstore.py	Adds unit test verifying that add_documents ignores user-provided IDs and returns item IDs
tests/requirements.txt	Updates dependencies to use pyenvector package and adds langchain-core and langchain-tests
tests/integration_tests/test_vectorstore.py	New integration test file implementing LangChain's standard vector store test suite
README.md	Clarifies environment variables needed for integration tests
.github/workflows/pr.yml	Adds langchain-tests installation to CI workflow

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[SongHyeopPark]

test에 필요한 dependency 설치 방법을 추가해주실수있으신가요?

[euphoria0-0]

test에 필요한 dependency 설치 방법을 추가해주실수있으신가요?

@SongHyeopPark 추가했습니다! c43351b