WIP: One Box V0

[0xnmn]

closes: https://linear.app/sourcegraph/issue/AI-154/surface-actual-code-not-just-filenames-into-the-cody-ui

• [x] https://linear.app/sourcegraph/issue/AI-201/do-intent-detection-and-automatically-open-context-files-accordion-for
• [ ] https://linear.app/sourcegraph/issue/AI-202/show-detected-intent-info-box
• [ ] https://linear.app/sourcegraph/issue/AI-203/detect-intent-while-the-user-is-typing-the-message
• [ ] https://linear.app/sourcegraph/issue/AI-204/update-submit-button-to-give-run-code-search-option
• [ ] https://linear.app/sourcegraph/issue/AI-205/show-code-snippets-for-context-files

Test plan

Changelog

coming soon