[franklinkim]

Description

Fix Error.Cause() to return wrapped error instead of nil, allowing proper error cause chain traversal. Also update Go to 1.27 and refresh dependencies.

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 💥 Breaking change
• 📝 Documentation
• ♻️ Refactoring
• ⚡ Performance
• ✅ Tests
• 🔧 Build/CI

Changes

• Fix Error.Cause() method to return the wrapped ErrCause instead of always returning nil
• Update Go version requirement to 1.27
• Refresh go.mod and go.sum dependencies
• Update .mise.toml, .golangci.yaml, and other build configuration files for Go 1.27 compatibility
• Update example and test module dependencies

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my own code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.