dream: websockets — upgrade + send/receive/close/broadcast + 16 tests

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/dream/conformance.sh

@@ -28,6 +28,7 @@ MODULES=(
   "lib/dream/session.sx"
   "lib/dream/flash.sx"
   "lib/dream/form.sx"
+  "lib/dream/websocket.sx"
 )
 
 # Suites: NAME RUNNER-FN PATH
@@ -38,6 +39,7 @@ SUITES=(
   "session     dream-ss-tests-run!  lib/dream/tests/session.sx"
   "flash       dream-fl-tests-run!  lib/dream/tests/flash.sx"
   "form        dream-fo-tests-run!  lib/dream/tests/form.sx"
+  "websocket   dream-ws-tests-run!  lib/dream/tests/websocket.sx"
 )
 
 TMPFILE=$(mktemp); trap "rm -f $TMPFILE" EXIT