feat: Integrate TypeScript SDK (spec 1.0) into diagram editor

[lornakelly]

Description

Add the Serverless Workflow TypeScript SDK (spec 1.0) to the diagram editor package and implement a lightweight wrapper module as the single point of interaction with the SDK across the codebase. For now the wrapper should expose functions for deserialization and validation, along with a parse function that combines both into a single call.

Motivation

The diagram editor needs to accept and process Serverless Workflow definitions in YAML or JSON format in a spec-compliant way. Wrapping the SDK behind a thin abstraction decouples the codebase from SDK-specific implementation details, making it easier to adapt as the spec evolves.

Proposed Implementation

No response

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.