fix: add cas_ref format to claude-code-detail turns schema

The turns array items in CLAUDE_CODE_DETAIL_SCHEMA were missing
format: 'cas_ref', so expandDeep in step-details couldn't resolve
turn hashes to their payloads. Hermes schema already had this.

小橘 <xiaoju@shazhou.work>

packages/workflow-agent-claude-code/src/schemas.ts

@@ -34,7 +34,7 @@ export const CLAUDE_CODE_DETAIL_SCHEMA: JSONSchema = {
     },
     turns: {
       type: "array",
-      items: { type: "string" },
+      items: { type: "string", format: "cas_ref" },
     },
   },
   additionalProperties: false,