refactor(console): restyle the first-run wizard and the credential-request page onto the kit #187

Summary

Restyle the two screens #157 left behind: the first-run wizard (src/components/first-run/*) and the "Make a credential request" page (src/pages/credential-request.tsx), onto the @cryptos-pki/ui kit. These are the only screens still outside the design review (#110): every other gate and route moved in #154, #175, #182 and #157. They're also the last importers of src/components/ui/button.tsx, src/components/ui/input.tsx, the local src/components/copy-block.tsx and src/components/key-backup-step.tsx, so this issue is where those four local primitives finally come out.

Acceptance criteria

• The first-run wizard (token, CA and admin steps) and the credential-request page match the kit's look in dark and light, at 1440 and 390 px wide, with their loading, empty, error and data states.
• src/components/ui/, src/components/copy-block.tsx and src/components/key-backup-step.tsx are deleted once nothing imports them.
• The existing tests stay green; any test edited because wording or layout changed on purpose is named in the PR.

Notes

• Visual only: routes, API calls and refusal wording stay the same (same rule refactor(console): restyle the access and audit screens and drop the local UI copies #157 followed).
• src/components/key-backup-step.tsx wraps key generation around a UI the kit's own KeyBackupStep now covers generically (see how credential-request-wizard.tsx did this in refactor(console): restyle the access and audit screens and drop the local UI copies #157's PR) — the new first-run admin step and the credential-request page can follow the same pattern.
• Part of feat(design): graphic design help for the web console #137.