fix: check stderr for json errors in TS -> Go call

[thomasschafer]

Pull Request Submission Checklist

• Follows CONTRIBUTING guidelines
• Commit messages
  are release-note ready, emphasizing
  what was changed, not how.
• Includes detailed description of changes
• Contains risk assessment (Low | Medium | High) - n/a
• Highlights breaking API changes (if applicable) - n/a
• Links to automated tests covering new functionality
• Includes manual testing instructions (if necessary)
• Updates relevant GitBook documentation (PR link: ___) - n/a
• Includes product update to be announced in the next stable release notes - n/a

What does this PR do?

Previously in the TS -> Go call performed by the uv plugin, JSON errors were assumed to be on stdout. However, from some testing they appear to be written to stderr, at least in the tests I've performed. This PR updates the error handling to check both sources.

How should this be manually tested?

In a uv project, add or remove a dependency in the pyproject.toml without updating the uv.lock. If you then run snyk monitor you should see the following error:

Monitoring <path/to/uv/project>...

{
  "ok": false,
  "error": "uv.lock is out of sync with pyproject.toml. Run `uv lock` to update the lockfile, or re-run with `--strict-out-of-sync=false` to test the outdated lockfile regardless.",
  "path": "/Users/thomasschafer/Development/Work/uv-goof/workspace"
}

On this branch you should instead see:

Monitoring <path/to/uv/project>...

uv.lock is out of sync with pyproject.toml. Run `uv lock` to update the lockfile, or re-run with `--strict-out-of-sync=false` to test the outdated lockfile regardless.

What's the product update that needs to be communicated to CLI users?

None

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.

[github-actions]

	Warnings
⚠️	You've modified files in src/ directory, but haven't updated anything in test folder. Is there something that could be tested?

Generated by 🚫 dangerJS against 30aa63c

[snyk-pr-review-bot]

PR Reviewer Guide 🔍

🧪 PR contains tests

🔒 No security concerns identified

⚡ No major issues detected

📚 Repository Context Analyzed This review considered 3 relevant code sections from 3 files (average relevance: 1.03) src/lib/plugins/uv/index.ts (lines 1-148) src/cli/main.ts (lines 1-516) src/cli/ipc.ts (lines 1-90)