fix(examples): pin patched Hono for Slidev

[rare]

Summary

• override the Slidev example's transitive Hono dependency to 4.12.34
• refresh only the matching lockfile entry
• clear GHSA-8j4g-w8fx-2239 from the repository validation gate

Verification

• npm ci
• npm audit --audit-level=moderate (0 vulnerabilities)
• npm run build

This is separated from Frontend Slides evidence PR #39 so the dependency repair remains independently reviewable.