dream: hello + counter demos + 10 end-to-end tests

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

lib/dream/conformance.sh

@@ -31,6 +31,8 @@ MODULES=(
   "lib/dream/websocket.sx"
   "lib/dream/static.sx"
   "lib/dream/run.sx"
+  "lib/dream/demos/hello.sx"
+  "lib/dream/demos/counter.sx"
 )
 
 # Suites: NAME RUNNER-FN PATH
@@ -44,6 +46,7 @@ SUITES=(
   "websocket   dream-ws-tests-run!  lib/dream/tests/websocket.sx"
   "static      dream-st-tests-run!  lib/dream/tests/static.sx"
   "run         dream-rn-tests-run!  lib/dream/tests/run.sx"
+  "demos       dream-dm-tests-run!  lib/dream/tests/demos.sx"
 )
 
 TMPFILE=$(mktemp); trap "rm -f $TMPFILE" EXIT