refactor: move generation settings to provider level, eliminate parameter passthrough

tests/test_provider_retry.py

@@ -2,7 +2,7 @@ import asyncio
 
 import pytest
 
-from nanobot.providers.base import LLMProvider, LLMResponse
+from nanobot.providers.base import GenerationSettings, LLMProvider, LLMResponse
 
 
 class ScriptedProvider(LLMProvider):
@@ -10,9 +10,11 @@ class ScriptedProvider(LLMProvider):
         super().__init__()
         self._responses = list(responses)
         self.calls = 0
+        self.last_kwargs: dict = {}
 
     async def chat(self, *args, **kwargs) -> LLMResponse:
         self.calls += 1
+        self.last_kwargs = kwargs
         response = self._responses.pop(0)
         if isinstance(response, BaseException):
             raise response
@@ -90,3 +92,34 @@ async def test_chat_with_retry_preserves_cancelled_error() -> None:
 
     with pytest.raises(asyncio.CancelledError):
         await provider.chat_with_retry(messages=[{"role": "user", "content": "hello"}])
+
+
+@pytest.mark.asyncio
+async def test_chat_with_retry_uses_provider_generation_defaults() -> None:
+    """When callers omit generation params, provider.generation defaults are used."""
+    provider = ScriptedProvider([LLMResponse(content="ok")])
+    provider.generation = GenerationSettings(temperature=0.2, max_tokens=321, reasoning_effort="high")
+
+    await provider.chat_with_retry(messages=[{"role": "user", "content": "hello"}])
+
+    assert provider.last_kwargs["temperature"] == 0.2
+    assert provider.last_kwargs["max_tokens"] == 321
+    assert provider.last_kwargs["reasoning_effort"] == "high"
+
+
+@pytest.mark.asyncio
+async def test_chat_with_retry_explicit_override_beats_defaults() -> None:
+    """Explicit kwargs should override provider.generation defaults."""
+    provider = ScriptedProvider([LLMResponse(content="ok")])
+    provider.generation = GenerationSettings(temperature=0.2, max_tokens=321, reasoning_effort="high")
+
+    await provider.chat_with_retry(
+        messages=[{"role": "user", "content": "hello"}],
+        temperature=0.9,
+        max_tokens=9999,
+        reasoning_effort="low",
+    )
+
+    assert provider.last_kwargs["temperature"] == 0.9
+    assert provider.last_kwargs["max_tokens"] == 9999
+    assert provider.last_kwargs["reasoning_effort"] == "low"