docs: Add session debrief about test fixes and MCP tool lesson

debug3.py

@@ -0,0 +1,15 @@
+with open("src/app_controller.py", "r", encoding="utf-8", newline="") as f:
+    content = f.read()
+
+# Add debug to see tracks
+old = """tracks = orchestrator_pm.generate_tracks(self.ui_epic_input, flat, file_items, history_summary=history)"""
+new = """tracks = orchestrator_pm.generate_tracks(self.ui_epic_input, flat, file_items, history_summary=history)
+    sys.stderr.write(f"[DEBUG] generate_tracks returned: {tracks}\\n")
+    sys.stderr.flush()"""
+
+content = content.replace(old, new)
+
+with open("src/app_controller.py", "w", encoding="utf-8", newline="") as f:
+    f.write(content)
+
+print("Added debug")