test: trim PostToolUse snapshot retries

examples/acp-agent/tests/snapshots/hook-codex-posttool-block/input.json

@@ -2,6 +2,6 @@
   "steps": [
     { "op": "initialize" },
     { "op": "newSession" },
-    { "op": "prompt", "text": "Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop." }
+    { "op": "prompt", "text": "Call the bash tool exactly once to run: echo HELLO. Whatever tool result comes back, quote it verbatim and stop without calling another tool." }
   ]
 }

examples/acp-agent/tests/snapshots/hook-codex-posttool-block/session.jsonl

@@ -1,6 +1,6 @@
 {"type":"session","version":0,"id":"7a5183c0-ec3a-46a8-a382-475eaa0c205b","createdAt":1783352220743,"cwd":"/tmp/acp-snap-cwd-vGnYqn"}
 {"type":"turn/start","seq":0,"time":1783352220747,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
-{"type":"user/message","seq":1,"time":1783352220748,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
+{"type":"user/message","seq":1,"time":1783352220748,"data":{"content":[{"type":"text","text":"Call the bash tool exactly once to run: echo HELLO. Whatever tool result comes back, quote it verbatim and stop without calling another tool."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352220749,"data":{"turn":1,"step":1}}
 {"type":"request/header","seq":3,"time":1783352220750,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352221451,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}