feat(core-trpc): scaffold tRPC client with React Query providers

- createTRPCContext + useTRPC hook for typed client access
- NextTrpcProvider with SSR-safe absolute URL resolution
- TanstackTrpcProvider for TanStack Start apps
- /api/trpc catch-all route handler in web-next
- Wire NextTrpcProvider into app providers
- Add @repo/core-trpc to transpilePackages

apps/web-next/next.config.mjs

@@ -16,6 +16,7 @@ const nextConfig = {
     "@repo/marketing-pages",
     "@repo/media",
     "@repo/navigation",
+    "@repo/core-trpc",
   ],
 };