feat: update prototype with new library styling

[AdamJ]

Description of changes

Update the prototype with the latest changes from caswow.library, along with improvements to layouts to accomodate updates.

PR checklist

Please check the boxes that apply before requesting review.

• I ran the site locally (pnpm show) and verified the changed pages
• I ran the production build (pnpm css && pnpm build) and checked docs/ output
• I updated or copied vendor assets using the package.json copy scripts if required (pnpm copy-css|copy-js|copy-fa|copy-cas)
• If this change depends on caswow.library, I documented whether it was linked with npm link or included in CI
• I verified there are no uncaught exceptions in the browser console (common: dialog script in base.njk)
• I added notes in this PR about any assumptions made (missing vendor files, local links, env variables)

Optional guidance for reviewers:

• For layout or JS changes, preview the affected page(s) in docs/ after a prod build.
• If vendor files were updated, confirm dependencies/ and docs/ contain the expected updated files.