Improve unit test coverage

[dhutchison]

Summary

• Expand behavioral unit coverage across tags, reusable components, API information, summaries, exports, and path-tree controls.
• Add regression coverage for reusable component sections and export payloads.
• Enforce minimum 80% line and 60% branch coverage in the verifier.
• Keep Cypress as functional end-to-end coverage without mixing it into Sonar unit coverage.

Validation

• 118 unit tests passing
• 17 Cypress scenarios passing
• 90.31% lines and 77.04% branches
• Lint and production build passing

Closes #35

[github-actions]

Thanks for the PR!

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud