fix(cli): set non-zero exit code when run command encounters errors

[kevinWangSheng]

Issue for this PR

Closes #14551

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

opencode run exits with code 0 even when the session encounters errors, breaking CI/CD pipelines. The fix awaits the event loop completion and sets process.exitCode = 1 when errors occurred.

How did you verify your code works?

Verified the exit code changes to 1 when the session produces errors. Only run.ts is modified.

Screenshots / recordings

N/A - no UI change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[sivanzcw]

I’m also seeing this issue. When opencode terminates unexpectedly, the exit code is not reported correctly. This PR would be very helpful — hope it can be merged soon.

[diandian1997]

Same issue. Running opencode run with benchmark with all exit codes 0, please consider fixing this bug.

[cokekitten]

Heads-up — I opened #26588 with a smaller alternative for the same bug (sets process.exitCode = 1 directly inside the session.error handler in loop(), +1 line). Apologies for the dup; I didn't notice this PR until github-actions surfaced it after I'd already pushed. Happy to close mine if you'd rather have yours go through — you've been waiting a while.