fix(pilot): freeze AI labels and enforce auditable execution

leanbench/llm.py

@@ -14,7 +14,7 @@ import re
 import time
 import urllib.error
 import urllib.request
-from collections.abc import Iterable
+from collections.abc import Callable, Iterable
 from dataclasses import dataclass, field
 from typing import Any, Protocol
 
@@ -66,6 +66,7 @@ class OpenAICompatibleClient:
     max_retries: int = 4
     temperature: float = 0.0
     usage: Usage = field(default_factory=Usage)
+    request_guard: Callable[[], None] | None = field(default=None, repr=False)
 
     @classmethod
     def from_settings(cls, settings: LLMSettings) -> OpenAICompatibleClient:
@@ -97,6 +98,8 @@ class OpenAICompatibleClient:
         }
         last: Exception | None = None
         for attempt in range(self.max_retries + 1):
+            if self.request_guard is not None:
+                self.request_guard()
             request = urllib.request.Request(url, data=body, headers=headers, method="POST")
             try:
                 with urllib.request.urlopen(request, timeout=self.timeout) as response: