SampleFailureMessageFormatter

Builds the failure message thrown when a docsTest sample fails.

The list of "excluded" sample-id substrings is loaded from the classpath resource /non-config-cache-compatible-snippets.txt. The same file is read by platforms/documentation/docs/build.gradle.kts to wire the excludeTestsMatching filter and the pre-flight check on --tests CLI patterns. That file is the single source of truth for samples skipped when enableConfigurationCacheForDocsTests=true.