fix: Use correct WitnessingMode values (OBSERVE, INTEGRATE)

WitnessingMode enum has OBSERVE, REFLECT, INTEGRATE, WITNESS_OTHER, MUTUAL.
Not SELF or HUMAN. Use OBSERVE for self-witnessing, INTEGRATE for human.

becomingone/api.py

@@ -189,7 +189,7 @@ def init_engine(
     
     # Create witnessing layer
     witnessing_layer = WitnessingLayer(
-        mode=WitnessingMode.HUMAN if witnessed_by_human else WitnessingMode.SELF,
+        mode=WitnessingMode.INTEGRATE if witnessed_by_human else WitnessingMode.OBSERVE,
         coherence_threshold=coherence_threshold,
     )