Segment demo video by scene with embedded GIF segments (#990)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomasnordquist <7721625+thomasnordquist@users.noreply.github.com>

tsconfig.json

@@ -28,6 +28,7 @@
     "src/spec/ui-tests-comprehensive.spec.ts",
     "src/spec/expandTopic.spec.ts",
     "src/spec/security-tests.spec.ts",
+    "src/spec/SceneBuilder.spec.ts",
     "scripts/*.ts"
   ],
   "exclude": ["node_modules"]