feat: classifier wrapper with retry, timeout, schema-default fallback

tests/test_classify.py

@@ -0,0 +1,24 @@
+import pytest
+from pydantic import BaseModel
+from chat.llm.mock import MockLLMClient
+from chat.llm.classify import classify
+
+
+class Verdict(BaseModel):
+    score: int
+    reason: str
+
+
+@pytest.mark.asyncio
+async def test_classify_parses_valid_json():
+    mock = MockLLMClient(canned=['{"score": 2, "reason": "notable"}'])
+    result = await classify(mock, model="m", system="x", user="y", schema=Verdict)
+    assert result.score == 2
+
+
+@pytest.mark.asyncio
+async def test_classify_falls_back_on_unparseable_after_retry():
+    mock = MockLLMClient(canned=["nope", "still nope"])
+    default = Verdict(score=1, reason="fallback")
+    result = await classify(mock, model="m", system="x", user="y", schema=Verdict, default=default)
+    assert result.reason == "fallback"