docs: add Sandbox Grouping Strategy section to Application Settings

[jpelletier1]

Summary

Document the Sandbox Grouping Strategy feature that was exposed to all users in OpenHands/OpenHands#14291.

Changes

• Added new Sandbox Grouping Strategy section to the Application Settings documentation
• Documented all 5 available strategies with clear descriptions:
  • No Grouping - Creates a new sandbox for each conversation (default)
  • Group by Newest - Adds to the most recently created sandbox
  • Least Recently Used - Adds to the oldest sandbox
  • Fewest Conversations - Adds to the least busy sandbox (load balancing)
  • Add to Any - Uses the first available sandbox
• Added note about shared state implications when using grouping strategies

Related

• Feature PR: APP-1546 feat(frontend): expose sandbox grouping strategy UI to all users OpenHands#14291

---

This PR was created by an AI agent (OpenHands) on behalf of the user.

[jpelletier1]

@tofarr Can you review these docs on Sandbox Strategy? It was identified as a feature in Local GUI that's not documented. Thanks!

[all-hands-bot]

🟢 Good taste - Clear documentation that follows the style guide.

The documentation is well-structured and provides helpful information about the Sandbox Grouping Strategy feature. A few minor clarifications would help users make more informed decisions about which strategy to use.

---

Was this automated review useful? React with 👍 or 👎 to this review to help us measure review quality.
Workflow run: https://github.com/OpenHands/docs/actions/runs/26173741100

[all-hands-bot]

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟢 LOW

This is a documentation-only change that adds clear, well-structured information about an existing feature. No code changes, no breaking changes, no security implications. The documentation follows the repository style guide and provides helpful information to users. The only improvements suggested are minor clarifications to help users better understand the different sandbox grouping strategies and make more informed choices.

VERDICT:
✅ Worth merging: Documentation is sound and follows best practices. The minor suggestions are optional improvements that would enhance user understanding but are not blockers.

KEY INSIGHT:
Documentation correctly documents the feature but could benefit from decision-making guidance to help users choose the right strategy for their use case.