fix(graphql): path traversal in GetChaosFault (#5606) - #5610

Proposed changes

Fixes #5606

Summary of Changes:

• Path Containment Check: Implemented isSubPath(baseDir, targetPath string) bool helper using standard Go filepath.Clean and filepath.Rel in chaoscenter/graphql/server/pkg/chaoshub/service.go.
• Root Directory Enforcement: Updated GetChaosFault to clean the ChaosHub faults directory path (cleanHubPath) and ensure basePath, csvPath, enginePath, and faultPath cannot escape cleanHubPath.
• Safe Rejection: Rejects any path traversal attempt (such as ../../../etc, pod-delete/../../etc, or absolute paths) with error invalid path: path traversal detected.
• Unit Tests: Added regression tests in chaoscenter/graphql/server/pkg/chaoshub/service_test.go covering:
  • Legitimate category & experiment path resolution
  • Relative path traversal (../../../etc)
  • Nested path traversal (pod-delete/../../etc)
  • Containment-prefix manipulation (../../test-hub-other/faults/pod-delete)
  • Absolute path resolution

Types of changes

What types of changes does your code introduce to Litmus? Put an x in the boxes that apply

• New feature (non-breaking change which adds functionality)
• Bugfix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices applies)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have signed the commit for DCO to be passed.
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added necessary documentation (if appropriate)

Dependency

• None

Special notes for your reviewer:

• Uses Go standard library primitives (path/filepath) for path resolution and containment checking without adding external dependencies.
• Verified locally with gofmt and go test -v . in chaoscenter/graphql/server/pkg/chaoshub.