Sync builders directory state to the URL

[Johnpii1]

close #369

Motivation
Provide a public, shareable builders directory whose filter, search, sort, and pagination state can be copied as a URL and navigated via browser history.
Persist directory controls in the query string so back/forward navigation and bookmarking produce the same filtered view.
Avoid creating a history entry per keystroke by debouncing search input and using replace navigation for search updates.

Description
Add a new builders route at app/builders/page.tsx that mounts a client BuildersView inside a Suspense boundary.
Add components/builders/use-builders.ts with useBuilders and useBuilderFilters hooks that call the backend endpoints (/users/directory and /users/directory/filters) and serialize query params.
Implement components/builders/builders-view.tsx, a URL-backed client directory that reads initial state from useSearchParams(), validates params, omits defaults when serializing, debounces search and uses router.replace for search and router.push for filter/sort/page changes, renders filter controls, skill chips, and paginated results.
Map API builder items to the existing BuilderCard view model and show skeletons / error / empty states; page size is 12 and default sort is newest.

Testing
Ran git diff --check with no reported problems.
Ran npm run lint (ESLint) which completed successfully.
Ran npx tsc --noEmit which passed type checking.
Ran npm run build which failed in this environment because Next.js could not fetch Google Fonts from fonts.googleapis.com, causing the production build to abort (network-restricted environment), not a code compile error.

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[Benjtalkshow]

Thanks! tsc and build pass here, but npm run lint fails at builders-view.tsx:122.

Blocking:

1. use-builders.ts:54 calls /users/directory/filters. Should be /users/filters, so filters 404 now.
2. builders-view.tsx:121 drops typed characters. Type abc, pause, type de fast.
3. :98 role is the account role, not a job title. Leave it out.
4. :92 id fallback makes links the profile route cannot open.

Please add a screenshot.