align agents/__init__.py with harness framing

Author: CrazyBoyM

agents/__init__.py

@@ -1,2 +1,3 @@
-# agents/ - Python teaching agents (s01-s12) + reference agent (s_full)
+# agents/ - Harness implementations (s01-s12) + full reference (s_full)
 # Each file is self-contained and runnable: python agents/s01_agent_loop.py
+# The model is the agent. These files are the harness.