fix(background-file) Manage path at git repository root directory Ref…

[Victor-D]

Description

fix(background-file) Manage path at git repository root directory

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactoring (no functional changes)
• Documentation update
• CI / Build / Tooling

How Has This Been Tested?

• make test passes locally
• Manual testing (describe below)

Quick tests such as ./dist/opencodereview review --repo $PWD -B ./../../../../misc/ocr/mycontext.md were done

Checklist

• My code follows the project's coding style (go fmt, go vet)
• I have performed a self-review of my code
• I have added tests that prove my fix is effective or my feature works
• New and existing unit tests pass locally with my changes
• I have updated the documentation accordingly (if applicable)
• I have signed the CLA

Related Issues

closes #324
#324

[github-actions]

✅ OpenCodeReview: No comments generated. Looks good to me.

[lizhengfeng101]

Nice fix! The implementation is clean and minimal — resolveBackgroundFilePath handles the three cases (empty, absolute, relative) correctly, and the test coverage is solid with both unit tests and an end-to-end scenario.

One suggestion: could you add a test case for when repoDir is an empty string? This would happen if --repo is not specified and repo detection fails. In that case filepath.Join("", relativePath) returns the relative path as-is, which is a reasonable fallback to the old behavior — but it would be good to have an explicit test documenting that expectation.

Other than that, LGTM. Thanks for the contribution!