In startMultiServerMode, status and pprof handlers were not registered,
causing /_status and /debug/pprof endpoints to return 404. Now these
handlers are registered on the server with default: true, consistent
with startVHostMode behavior. Also fixed cache API registration to
use default server instead of first server.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>