feat: create a package.json validation CI

[fantonangeli]

Description

Add a package.json validation CI to enforce that versions and license fields are the same across packages.

Motivation

Check that our package.json files have the right values, following our standard.

Proposed Implementation

Usinng syncpack and/or jq

Definition of Done

• Implementation: Fully implemented according to the Serverless Workflow spec.
• Unit Tests: Comprehensive unit tests are included and passing.
• Integration Tests: Verified within the monorepo and target environments (Web/VS Code).
• Documentation: Updated README.md, ADRs, or official docs.
• Performance: No significant regression in editor responsiveness.
• Accessibility: UI changes comply with accessibility standards.