fix timestamps in tuner accumelator (#335)

* fix timestamps in tuner accumelator

* chore: refactor strip_thought_ids_from_messages

---------

Co-authored-by: Abhishek Kumar <abhishek@a6k.me>

api/tests/test_message_sanitization.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from copy import deepcopy
+
+from pipecat.utils.context.message_sanitization import (
+    strip_thought_from_id,
+    strip_thought_ids_from_messages,
+)
+
+
+def test_strip_thought_from_id():
+    assert strip_thought_from_id("call_123__thought__abc") == "call_123"
+    assert strip_thought_from_id("call_123") == "call_123"
+    assert strip_thought_from_id(None) is None
+
+
+def test_strip_thought_ids_from_messages_does_not_mutate_input():
+    messages = [
+        {
+            "role": "assistant",
+            "tool_calls": [
+                {
+                    "id": "call_1__thought__hidden",
+                    "type": "function",
+                    "function": {"name": "lookup", "arguments": "{}"},
+                }
+            ],
+        },
+        {
+            "role": "tool",
+            "tool_call_id": "call_1__thought__hidden",
+            "content": '{"status":"ok"}',
+        },
+    ]
+    original = deepcopy(messages)
+
+    cleaned = strip_thought_ids_from_messages(messages)
+
+    assert messages == original
+    assert cleaned is not messages
+    assert cleaned[0]["tool_calls"][0]["id"] == "call_1"
+    assert cleaned[1]["tool_call_id"] == "call_1"