feat: Add built-in support for OpenAI and Anthropic LLM providers

[kshirajahere]

Summary

Currently, users who want to use OpenAI GPT or Anthropic Claude models must manually modify client_lib.py. This creates friction and makes the library less accessible.

Proposed Solution

Add optional client adapters for alternative LLM providers:

• OpenAI - GPT-4, GPT-4-turbo, GPT-4o, GPT-3.5-turbo
• Anthropic - Claude 3.5 Sonnet, Claude 3 Opus, Claude 3 Haiku

With optional pip dependencies:

pip install strategicwm[openai]
pip install strategicwm[anthropic]
pip install strategicwm[all-providers]