IBX-10066: Change lint config to 2.0

[GrabowskiM]

🎫 Issue	IBX-10066

Description:

For QA:

Documentation:

[Copilot]

Pull Request Overview

This PR updates the lint configuration to version 2.0 and adjusts the CI workflow for frontend builds.

• Introduces a new ESLint configuration file that leverages Ibexa’s shared config.
• Updates file matching patterns and bumps the Node.js version in the CI workflow.

Reviewed Changes

Copilot reviewed 3 out of 7 changed files in this pull request and generated no comments.

File	Description
eslint.config.mjs	Adds a new ESLint config file that imports and spreads the Ibexa config.
.github/workflows/frontend-ci.yaml	Modifies file matching patterns and updates Node.js version to 20.

Files not reviewed (4)

• .eslintrc.json: Language not supported
• ibexa.tsconfig.json: Language not supported
• package.json: Language not supported
• tsconfig.eslint.json: Language not supported

Comments suppressed due to low confidence (2)

.github/workflows/frontend-ci.yaml:6

• [nitpick] Verify that the updated file matching pattern '**.[cm]?[jt]sx?' accurately covers all intended file types without inadvertently including any unintended files.

- "**.[cm]?[jt]sx?"

.github/workflows/frontend-ci.yaml:26

• [nitpick] Confirm that upgrading to Node.js 20 is fully supported by all project dependencies and tests, and update documentation if necessary.

node-version: '20'