[gkatrakazas]

Summary

• Add a standalone TypeScript type-check script.
• Configure ESLint with recommended JavaScript and TypeScript rules, temporarily disabling rules with existing violations for a follow-up PR.
• Configure Prettier and ESLint compatibility, including EditorConfig checker support.
• Apply Prettier formatting across the project in a separate commit.
• Add Prettier and ESLint checks to pre-commit and CI.

Testing

• yarn typecheck
• yarn lint
• yarn format:check
• pre-commit validate-config

Before submitting

• I have read the Contribution Guidelines.