docs: Add setup & recommendations for local LLMs

[0xallam]

Extend the docs with a clear guide for running Strix using local models.

Include:

• Complete Ollama setup & installation steps
• Best recommended local models
• Hardware requirements & expected performance
• Example local model configuration for Strix

[yokoszn]

wip : https://github.com/TWN-Systems/strix-docs will submit a PR later tonight