Add a built-in require interface without globals

[lo1tuma]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: opt-out of globals #956
• Addresses an existing open issue: fixes 🛠️ Repo: Test "require interface" #2982
• Addresses an existing open issue: fixes 🚀 Feature: Export all BDD functions for "require interface" #2998
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

This adds require as a built-in interface so --ui require and ui: require work consistently from both the CLI and config files.

The interface keeps Mocha's DSL helpers off the global object and exposes the function-style APIs through require("mocha") and import { ... } from "mocha", including mixed BDD/TDD usage such as it with suite.

It also fills in the missing require-interface exports, extends the require-interface coverage to exercise the full callable API surface, updates --list-interfaces, and refreshes the docs for the require interface.