ci(ubicloud): build the GAL WebGL test app — 29 gal-webgl scenarios 404'd

First wx-suite run (27359020746): 262/262 non-GL tests passed; all 29
gal-webgl failures were galTest.isReady() timeouts because
gal_webgl_test.{js,wasm} are gitignored artifacts built by their own script
(build-gal-webgl-test.sh), which the workflow never ran — the page loaded
but the wasm 404'd. The script self-sources the local emsdk like
build-wasm-test.sh. Those 29 timeouts x3 attempts were also ~1.4h of the
1.7h e2e wall-clock.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/ci-ubicloud.yml

@@ -81,6 +81,12 @@ jobs:
       - name: Build wxWidgets test apps
         run: ./scripts/build-wasm-test.sh
 
+      # gal_webgl_test.{js,wasm} are gitignored build artifacts with their own
+      # build script — without this, all 29 gal-webgl scenarios time out on
+      # galTest.isReady() because the page 404s the wasm (run 27359020746).
+      - name: Build GAL WebGL test app
+        run: ./scripts/build-gal-webgl-test.sh
+
       - name: Install test deps
         working-directory: tests
         run: npm ci