fix(session): preserve user turns in replay history

nanobot/session/manager.py

@@ -19,6 +19,7 @@ from nanobot.utils.helpers import (
     estimate_message_tokens,
     find_legal_message_start,
     image_placeholder_text,
+    recent_message_start_index,
     safe_filename,
     strip_think,
 )
@@ -153,6 +154,7 @@ class Session:
         *,
         max_tokens: int = 0,
         include_timestamps: bool = False,
+        extend_to_user: bool = False,
     ) -> list[dict[str, Any]]:
         """Return unconsolidated messages for LLM input.
 
@@ -161,7 +163,12 @@ class Session:
         """
         unconsolidated = self.messages[self.last_consolidated:]
         max_messages = max_messages if max_messages > 0 else 120
-        sliced = unconsolidated[-max_messages:]
+        start_idx = recent_message_start_index(
+            unconsolidated,
+            max_messages,
+            extend_to_user=extend_to_user,
+        )
+        sliced = unconsolidated[start_idx:]
 
         # Avoid starting mid-turn when possible, except for proactive
         # assistant deliveries that the user may be replying to.