feat(markdown): thinking blocks between hidden tool calls collapse to the first one

tests/test_markdown_renderer.py

@@ -39,6 +39,23 @@ def test_thinking_renders_as_collapsed_callout() -> None:
     )
 
 
+def test_thinking_between_hidden_tool_calls_collapses_to_the_first() -> None:
+    message = _message(
+        ThinkingBlock(type="thinking", thinking="one", signature="s"),
+        ToolUseBlock(type="tool_use", id="t1", name="Read", input={}),
+        ThinkingBlock(type="thinking", thinking="two", signature="s"),
+        ToolUseBlock(type="tool_use", id="t2", name="Read", input={}),
+        ThinkingBlock(type="thinking", thinking="three", signature="s"),
+        TextBlock(type="text", text="answer"),
+        ThinkingBlock(type="thinking", thinking="four", signature="s"),
+        TextBlock(type="text", text="more"),
+    )
+    assert renderer.render_assistant_message(message) == (
+        "### Assistant:\n\n> [!thinking]-\n> one\n\nanswer\n\n"
+        "> [!thinking]-\n> four\n\nmore\n"
+    )
+
+
 def test_user_scaffold_matches_rendered_user_turn_shape() -> None:
     body = renderer.append_to_body("### Assistant:\n\nhi\n", renderer.USER_SCAFFOLD)
     assert body.endswith("\n\n---\n\n### User:\n\n")