Remove cssx.sx references from WASM test scripts

cssx.sx was deleted in the CSSX → ~tw migration. The test scripts
(test_wasm.sh, test_wasm_native.js, bisect_sxbc.sh) still referenced
it, causing ENOENT during WASM build step 5.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/browser/bisect_sxbc.sh

@@ -14,7 +14,7 @@ FILES=(
   render core-signals signals deps router page-helpers freeze
   bytecode compiler vm dom browser
   adapter-html adapter-sx adapter-dom
-  cssx boot-helpers hypersx
+  boot-helpers hypersx
   harness harness-reactive harness-web
   engine orchestration boot
 )

hosts/ocaml/browser/test_wasm.sh

@@ -211,7 +211,6 @@ node -e '
     "shared/static/wasm/sx/adapter-html.sx",
     "shared/static/wasm/sx/adapter-sx.sx",
     "shared/static/wasm/sx/adapter-dom.sx",
-    "shared/static/wasm/sx/cssx.sx",
     "shared/static/wasm/sx/boot-helpers.sx",
     "shared/static/wasm/sx/hypersx.sx",
     "shared/static/wasm/sx/engine.sx",

hosts/ocaml/browser/test_wasm_native.js

@@ -125,7 +125,7 @@ async function main() {
     'render', 'core-signals', 'signals', 'deps', 'router', 'page-helpers', 'freeze',
     'bytecode', 'compiler', 'vm', 'dom', 'browser',
     'adapter-html', 'adapter-sx', 'adapter-dom',
-    'cssx', 'boot-helpers', 'hypersx',
+    'boot-helpers', 'hypersx',
     'harness', 'harness-reactive', 'harness-web',
     'engine', 'orchestration', 'boot',
   ];