fix(opencode): preserve grep symlink paths

[remixz]

Issue for this PR

Closes #38582

Type of change

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

What does this PR do?

Grep canonicalized symlinked search paths and returned the real target path in its output. Subsequent tool calls could then fail external-directory permission checks configured for the original symlink path.

This keeps the canonical path for running ripgrep, but formats results relative to the path requested by the user.

How did you verify your code works?

Added regression coverage for searching through a directory symlink and verified that results contain the symlink path rather than the real path.

Ran bun test test/tool/grep.test.ts and verified with bun dev on a local build that the grep tool did indeed return the resolved path instead of real path.

Screenshots / recordings

N/A

Checklist

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

[github-actions]

Hey! Your PR title grep: Preserve symlink paths doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍

[opencode-agent]

The path reconstruction is scoped correctly: ripgrep still runs against the canonical cwd, while displayed matches are rebased onto the user-requested directory (or its parent for file inputs). The regression assertions cover both sides of the symlink-path invariant. No blocking issues found.