fix(onboard): recover from SSH 255 when sandbox was already created

[ericksoa]

Summary

• When openshell sandbox create exits with SSH 255 after printing "Created sandbox:", NemoClaw now treats this as recoverable instead of hard-exiting
• Added a final readyCheck in streamSandboxCreate on non-zero close to catch the race where the sandbox is already Ready when SSH dies
• In onboard.js, sandbox_create_incomplete failures now fall through to the existing 60s ready-wait loop instead of calling process.exit()

Root cause

Regression from #1516 (create-stream extraction) combined with #1081/#1527 (messaging provider migration forcing sandbox recreation). The create stream returns non-zero after "Created sandbox:" and NemoClaw exits before checking if the sandbox reached Ready state.

Test plan

• New unit tests: stream recovers when readyCheck is true at close time (SSH 255)
• New unit test: stream still returns non-zero when readyCheck is false at close time
• All existing sandbox-create-stream tests pass (7/7)
• All onboard integration tests pass (83/83)
• All src unit tests pass (538/538)
• Manual: trigger SSH 255 during sandbox create and verify recovery

Summary by CodeRabbit

• Bug Fixes
  • Enhanced sandbox creation error handling with improved failure classification and recovery messaging.
  • Improved sandbox readiness detection to prevent unnecessary creation failures when the sandbox is operational.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: aa92ed04-1fd8-40d9-81a6-e30f370b5bcc

📥 Commits

Reviewing files that changed from the base of the PR and between 4c38bfa and 48b39fb.

📒 Files selected for processing (3)

• bin/lib/onboard.js
• src/lib/sandbox-create-stream.test.ts
• src/lib/sandbox-create-stream.ts

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📝 Walkthrough

Walkthrough

This PR enhances sandbox creation error handling in two places: the onboard orchestrator now classifies creation failures and conditionally continues or exits, while the create-stream module adds a final readiness check when the child process exits with a non-zero code to override the error if the sandbox is actually ready.

Changes

Cohort / File(s)	Summary
Sandbox Creation Error Recovery bin/lib/onboard.js, src/lib/sandbox-create-stream.ts	Enhanced error handling with failure classification and readiness checks. Onboard now classifies creation failures and continues on sandbox_create_incomplete. Create-stream adds a synchronous final readiness check on non-zero child process exit to override errors when sandbox is already functional.
Creation Stream Tests src/lib/sandbox-create-stream.test.ts	Added two test cases covering child process close behavior: one where readiness check succeeds before close (overrides non-zero exit), another where readiness check fails (preserves non-zero exit status).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Poem

🐰 A sandbox born, but stumbling fast,
Yet readiness checked—it's here at last!
When child processes exit with a frown,
We check one more time before we're down.
Recovery blooms where errors stood before! 🌱

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly references the main fix: recovering from SSH exit code 255 when a sandbox was already created, which is the core objective of this PR.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/sandbox-create-ssh255-recovery

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