chore(design-system): relocate tight-scope components to page-scoped _components/

[myelinated-wackerow]

A component-disposition audit identified components in src/components/ with 2+ consumers whose consumer set is bound to a single page-area scope. Per the project's _components/ convention, they should live next to their consumers instead of in the shared src/components/ namespace.

Single PR. All items move + import-path updates + verify build/type-check.

Items

• src/components/Translatathon/ -> app/[locale]/contributing/translation-program/translatathon/_components/

  • Consumers: app/[locale]/contributing/translation-program/translatathon/leaderboard/page.tsx, src/layouts/md/Translatathon.tsx
  • Multiple .tsx files plus a constants.ts
  • Audit MDX-side references before moving: the MD layout consumer means a few MDX content files may reference these as shortcodes via src/layouts/md/Translatathon.tsx. Verify before the git mv.

• src/components/Search/ -> src/components/Nav/Search/

  • Consumers: Nav/DesktopNav.tsx, Nav/MobileNav.tsx (relative imports)
  • Already a Nav-scoped widget; move into the Nav unit

• src/components/LanguagePicker/ -> src/components/Nav/LanguagePicker/

  • Consumers: Nav/DesktopNav.tsx, Nav/MobileMenu/MobileMenuContent.tsx
  • Same pattern as Search

Verification before merge

• pnpm lint passes
• npx tsc --noEmit passes
• pnpm build passes
• All import sites of moved components updated
• No git grep "from \"@/components/<MovedName>" hits remaining

Out of scope

• Single-use components without a clear common page prefix -- tracked separately (single-use inline/relocate issues)
• Components in the storied or shared-infra buckets -- no relocation
• New stories or refactors of the moved components -- this is move-only

[github-actions]

This issue is stale because it has been open 30 days with no activity.