build(deps): bump locked anthropic to 1.2.0 + real-signature guard test

The `temperature` crash only reproduces on anthropic versions that removed the
parameter (1.2.0), which a fresh `pip install` already resolves (the constraint
is `anthropic>=0.86.0` with no upper bound); CI missed it only because the lock
pinned 0.116.0, which still has `temperature`.

- Bump the lockfile to anthropic 1.2.0 so CI runs against the version users
  actually get. Full unit suite + typecheck pass on 1.2.0.
- Add an integration guard that binds the SDK's actual create() kwargs against
  the real installed client signature, so forwarding any unsupported parameter
  fails in CI (on 1.2.0 this fails if the temperature fix is reverted).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: philipph-askui

pdm.lock

@@ -1,7 +1,10 @@
 """Unit tests for Anthropic messages API output_config / thinking handling."""
 
+import inspect
+from typing import Any
 from unittest.mock import MagicMock
 
+import anthropic
 from anthropic import omit
 
 from askui.models.anthropic.messages_api import (
@@ -130,3 +133,29 @@ def create(**kwargs: object) -> MagicMock:
             model_id="claude-sonnet-5",
         )
         assert isinstance(result, MessageParam)
+
+    def test_kwargs_accepted_by_real_client_signature(self) -> None:
+        """Integration guard: every kwarg the SDK sends must be accepted by the
+        REAL installed `anthropic` client's `beta.messages.create` signature.
+
+        This binds against the real signature (no network), so it fails if the
+        SDK forwards a parameter the installed client version does not support -
+        catching this class of breakage on whatever anthropic CI resolves."""
+        real_client = anthropic.Anthropic(api_key="dummy")
+        real_signature = inspect.signature(real_client.beta.messages.create)
+
+        def spy(**kwargs: Any) -> MagicMock:
+            # Raises TypeError if the SDK sends an unsupported keyword.
+            real_signature.bind(**kwargs)
+            response = MagicMock()
+            response.model_dump.return_value = {"role": "assistant", "content": "hi"}
+            return response
+
+        real_client.beta.messages.create = spy  # type: ignore[method-assign]
+        api = AnthropicMessagesApi(client=real_client)
+
+        result = api.create_message(
+            messages=[MessageParam(role="user", content="hi")],
+            model_id="claude-sonnet-5",
+        )
+        assert isinstance(result, MessageParam)