Create presence_demo.py

tools/presence_demo.py

@@ -0,0 +1,15 @@
+# presence_demo.py
+# Minimal stub: computes a dummy Presence Index p(t)
+# Replace with real logic when ready.
+
+def presence_dummy():
+    cra_sim = 0.7
+    A = 0.6
+    inertia = 0.1
+    reset = 0
+    z = cra_sim + A - inertia - reset
+    p = 1 / (1 + pow(2.718, -z))  # sigmoid
+    print(f"Dummy Presence Index p(t) = {p:.2f}")
+
+if __name__ == "__main__":
+    presence_dummy()