Fix ESLint v9 incompatibility with legacy .eslintrc.json configuration

[Copilot]

CI failing due to ESLint v9 requiring flat config format (eslint.config.js) instead of legacy .eslintrc.json.

Changes

Package dependencies:

• Downgrade eslint 9.39.2 → 8.57.0
• Downgrade eslint-plugin-github 6.0.0 → 5.1.8
• Replace typescript-eslint with explicit @typescript-eslint/eslint-plugin and @typescript-eslint/parser at v8.0.0
• Remove @eslint/js (ESLint v8 incompatible)

ESLint configuration:

• Remove deprecated formatting rules (func-call-spacing, semi, type-annotation-spacing) removed in typescript-eslint v8
• Disable import/no-unresolved (TypeScript handles import validation, avoids false positives with package.json exports)

{
  "rules": {
    "import/no-unresolved": "off"
  }
}

ESLint v8 maintains .eslintrc.json support, avoiding migration to flat config.

Original prompt

The CI build is failing due to an ESLint error that results in exit code 2. Log output references the ESLint migration guide, suggesting a misconfiguration or plugin version mismatch. Steps to resolve:

1. Verify and update package.json to ensure compatibility among eslint, eslint-plugin-github, @typescript-eslint/eslint-plugin, and @typescript-eslint/parser. Example:

"devDependencies": {
"eslint": "^8.0.0",
"eslint-plugin-github": "^4.3.1",
"@typescript-eslint/eslint-plugin": "^6.0.0",
"@typescript-eslint/parser": "^6.0.0"
}

2. Run npm install after updating dependencies.
3. Review .eslintrc.json for correct use of plugin:github/recommended and relevant rules.
4. Run npx eslint . locally to confirm there are no additional errors. If any plugin errors occur, install the missing plugins.

This should resolve the ESLint error and allow CI to pass.

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[github-actions]

Dependency Review

The following issues were found:

• ✅ 0 vulnerable package(s)
• ✅ 0 package(s) with incompatible licenses
• ✅ 0 package(s) with invalid SPDX license definitions
• ✅ 0 package(s) with unknown licenses.
• ⚠️ 4 packages with OpenSSF Scorecard issues.

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