Fix Buildkite analysis secret interpolation (#23109)

* Fix Buildkite analysis secret interpolation

* Pin Buildkite analysis plugin revision

Author: iangmaia

.buildkite/claude-analysis.yml

@@ -18,8 +18,8 @@ steps:
       - "/tmp/buildkite_logs_${BUILDKITE_BUILD_ID}.txt"
     plugins:
       - $CLAUDE_PLUGIN:
-          api_key: "$ANTHROPIC_API_KEY"
-          buildkite_api_token: "$BUILDKITE_TOKEN_FOR_CLAUDE"
+          api_key: "$$ANTHROPIC_API_KEY"
+          buildkite_api_token: "$$BUILDKITE_TOKEN_FOR_CLAUDE"
           analysis_level: "build"
           build_log_mode: "failed"
           trigger: "on-failure"

.buildkite/shared-pipeline-vars

@@ -5,4 +5,4 @@
 
 export CI_TOOLKIT="automattic/a8c-ci-toolkit#5.3.1"
 export TEST_COLLECTOR="test-collector#v1.10.1"
-export CLAUDE_PLUGIN="iangmaia/claude-summarize#iangmaia/add-build-log-mode"
+export CLAUDE_PLUGIN="iangmaia/claude-summarize#ce99c67dd57cdf236c3daca82b86a335fd5e9cc2"