V48 (impl-only): Fix gate UX test and dockerignore

Align demonstration-only fixture path with brittle patterns.
Allow containers/images/pipeliner/dist in monorepo dockerignore.

Author: geraldarthurdavis

.dockerignore

@@ -1,23 +1,24 @@
 # Used by Pipeliner docker build (context = monorepo root).
-# Source: images/pipeliner/.dockerignore
+# Keep in sync with containers/images/pipeliner/.dockerignore.
 
-# Context is monorepo root when building with -f images/pipeliner/Dockerfile
+# Context is monorepo root when building with
+# -f containers/images/pipeliner/Dockerfile
 .git
 .github
 **/.next
 **/coverage
 **/node_modules
 **/dist
-!images/pipeliner/dist
-!images/pipeliner/dist/**
+!containers/images/pipeliner/dist
+!containers/images/pipeliner/dist/**
 apps/uapi/.next
 apps/uapi/node_modules
 apps/uapi/storybook-static
 apps/uapi/tmp
 protocol-demonstration
 _legacy
 **/*.md
-!images/pipeliner/README.md
+!containers/images/pipeliner/README.md
 **/*.test.ts
 **/*.test.tsx
 **/__tests__

packages/btd/__tests__/interface-consumer-ux-regression-proof.test.ts

@@ -149,7 +149,8 @@ describe('Interface consumer UX regression proof', () => {
     expect(() =>
       buildBtdInterfaceConsumerUxRegressionRow({
         ...row,
-        fixturePath: 'scripts/specifying/src/consumer-fixture.test.ts',
+        // Must match BRITTLE_DEMONSTRATION_PATTERNS (protocol-demonstration|demo-only|mock-only).
+        fixturePath: 'protocol-demonstration/consumer-fixture.test.ts',
       }),
     ).toThrow(/demonstration-only/);
   });