Persistent AI Environments Beyond Ephemeral Sandboxes

[copernicusjones]

Summary

• Adds a technical article on persistent AI environments versus ephemeral sandboxes.
• Covers Daytona project configs, prebuilds, startup-time measurement, and the trade-offs of keeping state warm.
• Includes a comparison table, setup steps, a timing example, and a workflow diagram.

Validation

• markdownlint-cli check on the article markdown
• git diff --check

Closes #161