test: guard typed rate-limit retry test with importorskip("anthropic") (#113) (#114)

test_invoke_llm_with_retry_on_typed_rate_limit did a bare `import anthropic`,
so it failed with ModuleNotFoundError instead of skipping when the anthropic
extra isn't installed (e.g. `uv sync --extra openai` only). Mirrors the
existing pytest.importorskip("botocore") pattern used for Bedrock tests in
tests/test_llm.py (v0.6.1, M2).

Author: Brescou

tests/test_agents.py

@@ -277,7 +277,7 @@ def test_invoke_llm_with_retry_raises_after_max_attempts(self) -> None:
 
     def test_invoke_llm_with_retry_on_typed_rate_limit(self) -> None:
         """Typed SDK RateLimitError retries without '429' in the message."""
-        import anthropic
+        anthropic = pytest.importorskip("anthropic")
 
         mock_llm = MagicMock()
         mock_llm.bind_tools.return_value = mock_llm