fix(chat): persist/split <thinking>/<thought> blocks like stream UI

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_direct_loop_reasoning_split.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from oclaw.runtime.direct_loop import _split_reasoning_and_body
+
+
+def test_split_reasoning_extracts_thinking_tags() -> None:
+    chunks, body = _split_reasoning_and_body("<thinking>\ninner\n</thinking>\nvisible")
+    assert chunks == ["inner"]
+    assert body == "visible"
+
+
+def test_split_reasoning_extracts_thought_tags() -> None:
+    chunks, body = _split_reasoning_and_body("<thought>x</thought>after")
+    assert chunks == ["x"]
+    assert body == "after"
+
+
+def test_split_reasoning_explicit_when_no_tags() -> None:
+    chunks, body = _split_reasoning_and_body("body only", explicit_reasoning="  rc  ")
+    assert chunks == ["rc"]
+    assert body == "body only"
+
+
+def test_split_reasoning_antml_optional_prefix() -> None:
+    raw = "<antml:thinking>\nZ\n</antml:thinking>\nok"
+    chunks, body = _split_reasoning_and_body(raw)
+    assert chunks == ["Z"]
+    assert body == "ok"