fix(daytona): resume dormant managed sandboxes - #7828

Related issue

Part of #4676

Summary

• Daytona keeps a sandbox's files when it is stopped or archived, but Omnigent currently treats that sandbox as non-resumable. A later message can therefore replace it with an empty sandbox.
• Mark Daytona sandboxes as resumable and start the recorded sandbox ID. Wait if Daytona is already starting, stopping, restoring, or archiving it.
• Create a replacement only when Daytona reports that the sandbox is gone. API failures leave the existing binding alone so the user can retry.

ELI5: if a workspace is asleep, wake it up. Build a new one only if the old one was deleted.

next message -> stopped / archived -> start the same sandbox
             -> deleted            -> create a new sandbox
             -> API unavailable     -> keep the binding and return an error

Start review in omnigent/onboarding/sandboxes/daytona.py; the remaining changes are focused tests and the Daytona README update.

This does not add the separate park operation requested in #4676, so the issue should remain open.

Test Plan

• uv run --group test pytest tests/onboarding/sandboxes/test_daytona.py tests/server/test_managed_hosts.py -q -k 'test_daytona or resume_managed_host or run_managed_wake_recreates_a_definitively_gone_sandbox'
  • 42 passed, 356 deselected
• uv run --group dev pre-commit run --all-files
  • All hooks passed.
• Live Daytona check with a disposable sandbox:
  • Wrote a sentinel file, stopped the sandbox, and resumed it under the same ID. The file remained.
  • Stopped and archived the sandbox, then resumed it under the same ID. The file remained.
  • Deleted the sandbox afterward.

Demo

• Visual demo attached below
• Non-visual evidence provided below or in Test Plan
• Not applicable — no behavioral change

STOPPED -> STARTED: same ID, sentinel present
ARCHIVING -> ARCHIVED -> STARTED: same ID, sentinel present
cleanup: sandbox deleted

Type of change

• Bug fix
• Feature
• UI / frontend change
• Refactor / chore
• Docs
• Test / CI
• Breaking change

Test coverage

• Unit tests added / updated
• Integration tests added / updated
• E2E tests added / updated
• Manual verification completed
• Existing tests cover this change
• Not applicable

Coverage notes

The tests cover archived resume, a wake racing an archive, deleted sandboxes, and temporary API failures. The live check used the real Daytona API and confirmed that both the sandbox ID and its file survived stop and archive. No credential is stored in the repository or test fixtures.

Changelog

Daytona managed sessions now keep their workspace when a stopped or archived sandbox resumes.