feat(config): expand multi-LLM provider support (#18)

[saksham-jain177]

Pull Request

Description

Expands the configuration layer to support additional LLM providers using DSPy/LiteLLM.
This change is configuration- and documentation-only and does not modify agent or workflow logic.

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• ♻️ Code refactoring
• ⚡ Performance improvement
• ✅ Test addition or update

Changes Made

• Added configuration support for Google Gemini, Cohere, Azure OpenAI, Together AI, Replicate, and LM Studio.
• Extended provider validation and initialization logic in config.py.
• Added usage examples and provider notes to .env.example, README.md, and docs/getting-started/configuration.md.

Related Issues

Closes #18

Documentation

• Updated relevant documentation in docs/
• Updated README.md
• Updated docstrings and type hints
• No documentation changes needed

Checklist

• My code follows the project's code style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

This PR is intentionally limited to configuration and documentation changes.
Provider-specific runtime behavior is handled by DSPy/LiteLLM and underlying providers, and is not exercised in CI to avoid API-key and network-dependent tests.

[Dan-StrategicAutomation]

Will review in detail post release of v0.1.3