Clean up docs pages

[vinodmut]

The current docs pages is served at https://agenttoolkit.github.io/altk-evolve/

We need to make sure that material is complete and easy to navigate.

Some things to include:

• Rename Kaizen to Evolve
• Overview of Evolve, including architecture and approach
• Quickstart for Bob
• Quickstart for Claude Code
• Quickstart for Codex
• Demo examples, including links to videos
• Overview of results, including link to paper (see PR docs: restructure index page and add results page #154)

[visahak]

There is a quick start for codex #151 (which includes readme file that we can use)

[vinodmut]

The arch figure is a little hard to read in dark mode:

Looks good in light mode:

Where is the source for that image?

[visahak]

can we make the light mode the default one?