chore: import upstream snapshot with attribution

apps/sim/app/api/auth/providers/route.ts

@@ -0,0 +1,22 @@
+import type { NextRequest } from 'next/server'
+import { NextResponse } from 'next/server'
+import { getAuthProvidersContract } from '@/lib/api/contracts/auth'
+import { parseRequest } from '@/lib/api/server'
+import { isRegistrationDisabled } from '@/lib/core/config/env-flags'
+import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
+import { getOAuthProviderStatus } from '@/app/(auth)/components/oauth-provider-checker'
+
+export const dynamic = 'force-dynamic'
+
+export const GET = withRouteHandler(async (request: NextRequest) => {
+  const parsed = await parseRequest(getAuthProvidersContract, request, {})
+  if (!parsed.success) return parsed.response
+
+  const { githubAvailable, googleAvailable, microsoftAvailable } = await getOAuthProviderStatus()
+  return NextResponse.json({
+    githubAvailable,
+    googleAvailable,
+    microsoftAvailable,
+    registrationDisabled: isRegistrationDisabled,
+  })
+})