test(snapshot): update unlabeled workflow children

examples/acp-agent/tests/snapshots/advanced-toolchain/session.2.jsonl

@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783957884700,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783957884700,"data":{"content":[{"type":"text","text":"Reply with exactly WORKFLOW_CHILD_OK and nothing else."}],"source":{"kind":"user"},"role":"user","id":"a9ccad1e-ded5-4f5f-9419-a6bc440e96c3"},"surfaceOp":"append"}
 {"type":"session/title","seq":2,"time":1783957884700,"data":{"title":"Reply with exactly WORKFLOW_CHILD_OK and","messageSeqs":[1],"source":{"kind":"fallback"}}}
-{"type":"subagent/descriptor","seq":3,"time":1785534720833,"data":{"version":2,"mode":"one-shot","provider":"spawn","label":"workflow-child"}}
+{"type":"subagent/descriptor","seq":3,"time":1785534720833,"data":{"version":2,"mode":"one-shot","provider":"spawn"}}
 {"type":"user/message","seq":4,"time":1785534720834,"data":{"content":[{"type":"text","text":"Current runtime context. This snapshot supersedes earlier runtime-context snapshots.\n\nCurrent DSH file policy: danger-full-access. The DSH file sandbox does not restrict file modifications by available operations.\n\nApproval prompts are disabled in this session: actions that require approval are rejected automatically — do not request sandbox escalation (do not set `sandbox_permissions`)."}],"source":{"kind":"plugin","plugin":"@deepseek-ai/dsh-system-prompt"},"role":"user","id":"253f3d13-7f37-430b-8dc8-ce9ee53f1ddc"},"surfaceOp":"append"}
 {"type":"step/start","seq":5,"time":1785534720834,"data":{"turn":1,"step":1}}
 {"type":"request/header","seq":6,"time":1785534720835,"data":{"header":{"config":{"provider":"deepseek-official","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}

examples/acp-agent/tests/snapshots/workflow-run/session.1.jsonl

@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783600636316,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783600636316,"data":{"content":[{"type":"text","text":"Reply with exactly the word WF_CHILD_OK and nothing else."}],"source":{"kind":"user"},"role":"user","id":"a7990b4d-9b1d-47de-883b-47f6755c2b9b"},"surfaceOp":"append"}
 {"type":"session/title","seq":2,"time":1783600636316,"data":{"title":"Reply with exactly the word","messageSeqs":[1],"source":{"kind":"fallback"}}}
-{"type":"subagent/descriptor","seq":3,"time":1785534719523,"data":{"version":2,"mode":"one-shot","provider":"spawn","label":"Reply with exactly the word WF_CHILD_OK and not…"}}
+{"type":"subagent/descriptor","seq":3,"time":1785534719523,"data":{"version":2,"mode":"one-shot","provider":"spawn"}}
 {"type":"user/message","seq":4,"time":1785534719523,"data":{"content":[{"type":"text","text":"Current runtime context. This snapshot supersedes earlier runtime-context snapshots.\n\nCurrent DSH file policy: danger-full-access. The DSH file sandbox does not restrict file modifications by available operations.\n\nApproval prompts are disabled in this session: actions that require approval are rejected automatically — do not request sandbox escalation (do not set `sandbox_permissions`)."}],"source":{"kind":"plugin","plugin":"@deepseek-ai/dsh-system-prompt"},"role":"user","id":"44d0e7d4-c05c-446d-afd2-28b2a9aec7e8"},"surfaceOp":"append"}
 {"type":"step/start","seq":5,"time":1785534719523,"data":{"turn":1,"step":1}}
 {"type":"request/header","seq":6,"time":1785534719523,"data":{"header":{"config":{"provider":"deepseek-official","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}