chore: add MIT LICENSE - #220

Closes #207

Summary

Resolves the missing license issue by adding an explicit MIT License to the repository root. This ensures that the repository has explicit licensing, providing contributors and downstream users with legal permission to use, modify, and redistribute the code.

Related Issue

Closes #207

Changes Made

• Added an MIT LICENSE file at the repository root.
• Set the copyright line to: Copyright (c) 2026 Vero Core Engine contributors.
• Updated the README.md to reference the newly added MIT license instead of the previous Apache-2.0 placeholder badge and text.

Testing Performed

• Unit tests pass (cargo test / npm test)
• Integration tests pass
• Manual smoke test performed (verified LICENSE and README.md formatting locally)

Checklist

• Branch follows naming convention (feat/, fix/, chore/, etc.)
• Closes #NUM reference is present above (linking this PR to the issue)
• Code follows the project's style and conventions
• New or updated tests cover the changes (N/A - Non-code change)
• Documentation updated if behaviour changed (N/A - Non-code change)
• No secrets, credentials, or sensitive data committed
• PR is scoped to a single concern (one issue per PR)