Draft codejail service approach doc

[robrap]

Assorted documentation tasks, including drafting an approach doc.

Acceptance Criteria:

• Draft approach doc. Note Python upgrade of Codejail.
• [discovery] Catalog existing 2U codejail docs and ticket follow-up.
• Document or ticket rollout plan for Stage/Edge/Prod.

Additional notes/questions:

• Draft requirements:
  • Codejail must be deployed as its own service.
  • The new service must provide the same functional results, including security.
  • The new service must provide similar or improved observability, performance, reliability, and all other technical requirements.
  • Any enhancements should be articulated.
• Document SRE dependencies; and SRE support planning to avoid blocking.
• See codejail working doc: https://docs.google.com/document/d/1BbWAIgSQ22uZ0Q7QLHFvUmD6v_5ipmkymgF3ixclIu8/edit?tab=t.0
• Who are stakeholders? Who needs to review?