feat: Highlight edge path on selection #186

Description

Improve edge selection style and highlight edge path making it easy to visually follow edge's path.

Motivation

Merging edges cause edges with the same path to overlap at some point and it is hard to identify where they are actually going.
The edge selection styling and color is too washed making it is hard to identify if an edge is really selected.

Proposed Implementation

When an edge is selected:

• The edge shall be moved to the top of the others making it fully be visible.
• The edge selection styling and color must highlight to the select edge and its path.

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.