Add TypeScript typecheck script and run typecheck in frontend CI

[AdrianOrlow]

Motivation

• Enforce TypeScript correctness during CI to catch type errors early in the frontend pipeline.
• Ensure the codebase is compatible with stricter tsc checks by removing unused imports that would fail typechecking.

Description

• Add a typecheck npm script that runs tsc -b by updating package.json.
• Insert a Typecheck step that runs yarn typecheck before the Build step in both the build and unit jobs of .github/workflows/build-frontend.yml.
• Fix a test file by removing an unused default React import in src/components/ui/Select/ActionList/ActionList.test.tsx so tsc does not report TS6133.

Testing

• Ran yarn typecheck, which initially failed with TS6133 due to an unused React import.
• After removing the unused import, yarn typecheck was run again and completed successfully.

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Codex Task

[github-actions]

Coverage Report

Coverage after merging codex/create-pr-from-issue-104-branch into main will be:

	Hit/ Total	Coverage
🟰 Statements	335 / 335	100% 🥳
🌿 Branches	412 / 412	100% 🥳
🔢 Functions	87 / 87	100% 🥳
📝 Elements	834 / 834	100% 🥳