fix: cbs reverse, setdefaultvar

[tammy3211]

PR Checklist

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Summary

fix cbs reverse, setdefaultvar

Related Issues

"None".

Changes

fix cbs reverse, setdefaultvar

Impact

Additional Notes

Footnotes

1. Modifies the behavior of prompting, requesting, or handling responses from AI models. ↩

2. Over 80% of the code is AI generated. ↩

[sub-hub]

Every fix is a small fix, and the bugs are critical. Thank you for the PR.

Just one thing: there was a test for reverse cbs in the strings.test.ts file, but it had been skipped because it was failing.
Since this PR fixes that error, it seems like a good to stop skipping the reverse test in this PR too.

[sub-hub]

Now the reverse test is working properly. Thank you!

[cubicj]

Verified the CBS behavior. setdefaultvar now treats the existing getChatVar() "null" sentinel as unset, and reverse now operates on the parsed argument instead of the whole CBS match.

Check, tests, and build pass locally.

Approving — thanks for the contribution!