Docs: [AEA-0000] - couple of suggestions after cdk work

[tstephen-nhs]

Summary

• Routine Change

Details

• guidance on CDK unit tests focused on consumer products (not eps-cdk-utils)
• avoid a couple of TypeScript preferences of Copilot unappreciated by Sonarqube

[github-actions]

This PR is linked to a ticket in an NHS Digital JIRA Project. Here's a handy link to the ticket:

AEA-0000

[Copilot]

Pull request overview

Updates internal Copilot guidance docs to better align TypeScript/CDK recommendations with preferred testing patterns and linting expectations.

Changes:

• Add TypeScript guidance to avoid using the void operator as a lint-warning suppression mechanism.
• Add TypeScript style guidance preferring Array<T> over T[] for array annotations.
• Add CDK unit testing guidance focused on synth/assertion tests and add a CDK test command to validation steps.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.github/instructions/languages/typescript.instructions.md	Adds TypeScript-specific style guidance to steer generated/reviewed code away from patterns that can trigger tooling warnings.
.github/instructions/languages/cdk.instructions.md	Documents recommended CDK unit test approaches (synth-based assertions) and adds a workspace test command for CDK packages.