fix(sandbox): GNU grep fallback when ripgrep is unavailable

[guitavano]

Summary

• Adds a GNU grep fallback for the sandbox grep tool when rg is not on PATH (common in user-desktop dev), while keeping ripgrep as the preferred backend in Docker/K8s sandboxes.
• Normalizes grep output for all backends: repo-relative paths, accurate matchCount when context is set, and friendly 400 errors for invalid regex.
• Expands brace globs ({ts,tsx}) and line-start patterns for the GNU grep path.

Test plan

• bun test packages/sandbox/daemon/routes/grep-search.test.ts
• bun test packages/sandbox/daemon/routes/fs.test.ts
• Manual grep tool checks: content/files/count modes, context, case-insensitive, brace globs, invalid regex
• Verified prod sandbox (ripgrep present) behavior unchanged

Made with Cursor

---

Summary by cubic

Adds a GNU grep fallback for the sandbox search tool when rg isn’t available, while keeping ripgrep preferred. Normalizes output across backends with repo-relative paths and accurate match counts.

• Bug Fixes

  • Fallback to GNU grep when rg is missing; supports brace globs and line-start patterns.
  • Normalize results: repo-relative paths and matchCount excludes context lines.
  • Return 400 with clear message for invalid regex.

• Refactors

  • Extracted grep handler to packages/sandbox/daemon/routes/grep-search.ts; fs.ts re-exports makeGrepHandler.
  • Expanded tests to cover both backends, glob handling, and error cases.
  • Updated Decopilot tool description to reflect backend preference.

^{Written for commit 956f438. Summary will update on new commits.}

[github-actions]

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[github-actions]

Release Options

Suggested: Patch (2.371.2) — based on fix: prefix

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Reaction	Type	Next Version
👍	Prerelease	2.371.2-alpha.1
🎉	Patch	2.371.2
❤️	Minor	2.372.0
🚀	Major	3.0.0

Current version: 2.371.1

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