test(demo): intentional FAIL for live_heap CI exclude wiring (#168)

Demo-only: ci.yml drops python_live_heap_3.14 from test_scenarios_exclude
while list-scenarios unit test still expects it excluded. Restore exclude
regexp to demo PASS.

Author: vlad-scherbich

.github/workflows/ci.yml

@@ -66,7 +66,7 @@ jobs:
       # exclude rather than a lookahead baked into test_scenarios.
       # Additional wheel-only 3.14 dirs (e.g. live_heap) are added to this list
       # when those scenarios land.
-      test_scenarios_exclude: '_3\.15$|^python_live_heap_3\.14$|^python_downstream_gate$'
+      test_scenarios_exclude: '_3\.15$|^python_downstream_gate$'  # DEMO_FAIL: restore live_heap exclude to demo PASS
     secrets: inherit
   full_host:
     uses: ./.github/workflows/test.yml