chore: add minimal eslint config

[Menefail]

Added a lightweight lint baseline that’s easy to expand later

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Note

Sets up a baseline ESLint configuration for the repository.

• Adds .eslintrc.json with root: true, env for es2021 and node
• Extends eslint:recommended and sets parser options (ecmaVersion: 2021, sourceType: module)

^{Written by Cursor Bugbot for commit 0991fe4. This will update automatically on new commits. Configure here.}