fix(agent): avoid truncate_text name shadowing

Rename the boolean flag in _sanitize_persisted_blocks and alias the imported helper so session persistence cannot crash with TypeError when truncation is enabled.

tests/test_truncate_text_shadowing.py

@@ -0,0 +1,31 @@
+import inspect
+from types import SimpleNamespace
+
+
+def test_sanitize_persisted_blocks_truncate_text_shadowing_regression() -> None:
+    """Regression: avoid bool param shadowing imported truncate_text.
+
+    Buggy behavior (historical):
+    - loop.py imports `truncate_text` from helpers
+    - `_sanitize_persisted_blocks(..., truncate_text: bool=...)` uses same name
+    - when called with `truncate_text=True`, function body executes `truncate_text(text, ...)`
+      which resolves to bool and raises `TypeError: 'bool' object is not callable`.
+
+    This test asserts the fixed API exists and truncation works without raising.
+    """
+
+    from nanobot.agent.loop import AgentLoop
+
+    sig = inspect.signature(AgentLoop._sanitize_persisted_blocks)
+    assert "should_truncate_text" in sig.parameters
+    assert "truncate_text" not in sig.parameters
+
+    dummy = SimpleNamespace(max_tool_result_chars=5)
+    content = [{"type": "text", "text": "0123456789"}]
+
+    out = AgentLoop._sanitize_persisted_blocks(dummy, content, should_truncate_text=True)
+    assert isinstance(out, list)
+    assert out and out[0]["type"] == "text"
+    assert isinstance(out[0]["text"], str)
+    assert out[0]["text"] != content[0]["text"]
+