implement session management in agent harness

agent-sessions/tools/interaction.py

@@ -0,0 +1,8 @@
+def ask_question(question: str) -> str:
+    """Ask the user a clarifying question and return their answer."""
+    print(f"\n  [agent] {question}")
+    try:
+        answer = input("  Your answer: ").strip()
+    except EOFError:
+        return "(no answer, EOF)"
+    return answer if answer else "(no answer provided)"