[Snyk] Security upgrade eslint from 8.42.0 to 9.0.0

[mnk-blr]

Snyk has created this PR to fix 1 vulnerabilities in the pnpm dependencies of this project.

Snyk changed the following file(s):

• playground/app/package.json

⚠️ Warning

Failed to update the pnpm-lock.yaml, please update manually before merging.

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Uncontrolled Recursion SNYK-JS-FLATTED-15518041	170

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[github-actions]

File	Coverage
All files	88%	✅
src/main/custom-chart-context.ts	86%	✅
src/main/logger.ts	88%	✅
src/main/post-message-event-bridge.ts	77%	✅
src/react/use-custom-chart-context.tsx	86%	✅
src/react/mocks/custom-chart-context-mock.ts	96%	✅
src/utils/chart-config.ts	82%	✅
src/utils/date-formatting.ts	82%	✅
src/utils/formatting-util.ts	89%	✅
src/utils/conditional-formatting/conditional-formatting.ts	92%	✅
src/utils/globalize-Initializer/globalize-utils.ts	95%	✅
src/utils/number-formatting/number-formatting-utils.ts	98%	✅
src/utils/number-formatting/number-formatting.ts	90%	✅

Minimum allowed coverage is 0%

Generated by 🐒 cobertura-action against c927071

[claude]

⚠️ BREAKING CHANGE: This ESLint v9 upgrade introduces critical compatibility issues:

1. Plugin Incompatibility: @typescript-eslint/parser v5.59.0 is incompatible with ESLint v9. You need to upgrade to @typescript-eslint/parser: "^7.0.0" for ESLint v9 compatibility.

2. Configuration Breaking Change: ESLint v9 deprecates .eslintrc.* files in favor of flat config (eslint.config.js). The current .eslintrc.cjs will generate warnings/errors.

3. Missing CI Coverage: The playground app's linting isn't tested in CI, so this breaking change won't be caught by automated testing.

Recommendation: Either:

• Revert this change and coordinate a proper migration with all plugin updates
• Or update all related TypeScript ESLint plugins and migrate to flat config format

[claude]

PR Review Summary

This PR upgrades ESLint from v8.38.0 to v9.0.0 in the playground app, but introduces critical compatibility issues that make it NOT READY TO MERGE.

Critical Issues Found:

1. Plugin Compatibility Breakage: The current @typescript-eslint/parser v5.59.0 is incompatible with ESLint v9, which will cause build/linting failures.

2. Configuration Format Deprecation: ESLint v9 deprecates .eslintrc.* files. The playground's .eslintrc.cjs needs migration to flat config format.

3. Missing CI Coverage: The playground app's linting isn't included in CI workflows, so this breaking change won't be caught automatically.

4. Incomplete Upgrade: This is a partial upgrade that breaks existing tooling without updating dependent plugins.

Required Actions Before Merge:

• Update @typescript-eslint/parser to v7+ for ESLint v9 compatibility
• Update @typescript-eslint/eslint-plugin accordingly
• Migrate .eslintrc.cjs to flat config format
• Add playground linting to CI pipeline
• Test all linting functionality after updates

Review Status:

• Code Quality: Breaking changes found
• Documentation: No updates needed
• Test Coverage: Missing CI validation

Verdict: This PR requires significant additional work before it's safe to merge. Consider coordinating a comprehensive ESLint v9 migration rather than this isolated upgrade.