fix(tests): isolate env in resolve_google_judge_api_key test

The second assertion in test_resolve_google_judge_api_key_prefers_google_key
ran outside the mock.patch.dict context. When GOOGLE_API_KEY or GEMINI_API_KEY
is set in the real environment, os.environ takes precedence over the config
dict fallback and the test fails.

Wrap the assertion in its own mock.patch.dict scope that clears the three
relevant env vars so the test passes regardless of the developer's env.

This contribution was developed with AI assistance (Claude Code).

tests/test_evaluator_v3.py

@@ -1,4 +1,5 @@
 import json
+import os
 import sys
 import tempfile
 import unittest
@@ -99,7 +100,10 @@ class EvaluatorV3Tests(unittest.TestCase):
     def test_resolve_google_judge_api_key_prefers_google_key(self):
         with mock.patch.dict("os.environ", {"GOOGLE_API_KEY": "google", "GEMINI_API_KEY": "gemini"}, clear=False):
             self.assertEqual("google", evaluator.resolve_google_judge_api_key({}))
-        self.assertEqual("fallback", evaluator.resolve_google_judge_api_key({"GOOGLE_GENAI_API_KEY": "fallback"}))
+        with mock.patch.dict("os.environ", {k: "" for k in ("GOOGLE_API_KEY", "GEMINI_API_KEY", "GOOGLE_GENAI_API_KEY")}, clear=False):
+            for k in ("GOOGLE_API_KEY", "GEMINI_API_KEY", "GOOGLE_GENAI_API_KEY"):
+                os.environ.pop(k, None)
+            self.assertEqual("fallback", evaluator.resolve_google_judge_api_key({"GOOGLE_GENAI_API_KEY": "fallback"}))
 
     def test_extract_gemini_text_raises_when_missing(self):
         self.assertEqual(