Fix stale test assertions and truthsocial pytest dependency

- test_models: update xAI model expectations to grok-4-1-fast (matching
  current XAI_POLICY_MAP)
- test_openai_reddit: update fallback order assertion to gpt-4.1 (matching
  current MODEL_FALLBACK_ORDER)
- test_codex_auth: expect 'reddit' not 'web' when no API keys (Reddit
  is available via public JSON fallback)
- test_truthsocial: convert from pytest-style classes to unittest.TestCase,
  fix import path to use sys.path.insert pattern (matching all other tests)

tests/test_models.py

@@ -84,7 +84,7 @@ class TestSelectXAIModel(unittest.TestCase):
             "fake-key",
             policy="latest"
         )
-        self.assertEqual(result, "grok-4-latest")
+        self.assertEqual(result, "grok-4-1-fast")
 
     def test_stable_policy(self):
         # Clear cache first to avoid interference
@@ -94,7 +94,7 @@ class TestSelectXAIModel(unittest.TestCase):
             "fake-key",
             policy="stable"
         )
-        self.assertEqual(result, "grok-4")
+        self.assertEqual(result, "grok-4-1-fast")
 
     def test_pinned_policy(self):
         result = models.select_xai_model(
@@ -125,10 +125,10 @@ class TestGetModels(unittest.TestCase):
             "XAI_API_KEY": "xai-test",
         }
         mock_openai = [{"id": "gpt-5.2", "created": 1704067200}]
-        mock_xai = [{"id": "grok-4-latest", "created": 1704067200}]
+        mock_xai = [{"id": "grok-4-1-fast", "created": 1704067200}]
         result = models.get_models(config, mock_openai, mock_xai)
         self.assertEqual(result["openai"], "gpt-5.2")
-        self.assertEqual(result["xai"], "grok-4-latest")
+        self.assertEqual(result["xai"], "grok-4-1-fast")
 
 
 if __name__ == "__main__":