Motivation

• Increase unit test coverage for configuration utilities and plugin registry paths that previously had little or no coverage.
• Validate formatting and error messages (ValidationError.Error, GetConfigHelp, stripComments) to ensure helpful diagnostics.
• Exercise plugin discovery and manifest handling for success and failure paths in Registry.LoadPlugins to catch edge cases.

Description

• Added internal/config/config_help_test.go which tests ValidationError.Error, GetConfigHelp, stripComments, and getStringEnv comment-stripping behavior.
• Added internal/checks/registry_plugins_test.go which tests Registry.LoadPlugins for the no-registry case, successful plugin loading from a directory, and propagation of plugin load errors.
• Tests follow project conventions (use of testify/require, table-driven style where appropriate) and do not change production code.

Testing

• Ran the repository test suite with magex test and magex test:cover, which executed the new tests (new tests passed) but the overall test run failed due to unrelated pre-existing failures in other packages (notably cmd/go-pre-commit/cmd plugin tests, builtin EOF/whitespace permission cases, and git installer tests).
• Verified targeted packages: internal/config and internal/checks exercised the added tests and increased coverage for the targeted functions.
• No production code changes were required; only test files were added to improve coverage and signal on edge cases.
• Assignees: @mrz1836

Codex Task