fix: resolve setuptools packaging, Rag SDK NoneType crash, load balancer fallback logic, and add test suites

[ankitnarang-ai]

This PR resolves several critical issues across packaging, the Python SDK, load balancer services, and test coverage.

1. 📦 Packaging & Build System (pyproject.toml)

• Configured explicit [tool.setuptools.packages.find] to restrict package discovery strictly to npmai*.
• Fixes Multiple top-level packages discovered in a flat-layout errors during pip install . and pip install -e ..
• Added .gitignore to prevent committing .venv/, __pycache__, *.egg-info/, and test artifacts.

2. 🐍 Python SDK (npmai/npmai.py)

• Fixed TypeError in Rag.send(): Fixes crash when files=None or omitted (e.g., for URL/link-based queries).
• Resource Cleanup: Safely opens and closes file handles via a try...finally block.
• State Isolation: Resets files_to_send per send() invocation.

3. ⚖️ Load Balancer Service (load_balancer/app.py)

• Enhanced Fallback Model Resolution: Updated llm_router fallback lookup to resolve both standard model names (e.g. gemma2:2b) and _fall model names.
• Standard HTTP Status Codes: Replaced non-standard HTTP status codes (444 and 402) with standard 400 Bad Request and 404 Not Found.

4. 🔗 API Framework (NPMRAG-API-Framework/NPMRAG-API-Framework.py)

• Replaced Python string identity check anti-patterns (is not "", is "") with value equality (!= "", == "") to eliminate Python warnings.

5. 🧪 Testing & Verification

• JavaScript SDK (npmai_js/package.json): Configured "test": "node --test tests/*.test.js" script (Passed 49/49 unit tests).
• Python SDK (tests/test_sdk.py): Added unit test suite covering Ollama, Memory, and Rag classes (Passed 12/12 pytest tests).

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Verification

• ✅ pip install -e . built and installed successfully.
• ✅ pytest tests/ (12 passed)
• ✅ cd npmai_js && npm test (49 passed)

[sonuramashishnpm]

We will soon aproove it as we are finalised with our new updates we will approve your changes.