ci: update evaluation model to claude-opus-4-1 and set CLOUD_ML_REGION env var

Author: omkargaikwad23

evals/claude_code_model.yaml

@@ -14,13 +14,14 @@
 
 claude_code_version: "@anthropic-ai/claude-code@2.1.85"
 generator: claude_code
-model: "claude-opus-4-6"
+model: "claude-opus-4-1@20250805"
 
 use_vertex: true
 vertex_project_id: "${GOOGLE_CLOUD_PROJECT}"
 vertex_region: "us-east5"
 
 env:
+  CLOUD_ML_REGION: "us-east5"
   GOOGLE_CLOUD_PROJECT: "${GOOGLE_CLOUD_PROJECT}"
   CLOUD_SQL_POSTGRES_PROJECT: "${CLOUD_SQL_POSTGRES_PROJECT}"
   CLOUD_SQL_POSTGRES_INSTANCE: "${CLOUD_SQL_POSTGRES_INSTANCE}"