feat: add fraud detection validator

tests/test_contracts_settlement.py

@@ -59,3 +59,23 @@ def test_epoch_settlement_debits_clients_and_rewards_nodes_and_validator():
     assert contracts.settlement.get_token_balance("node-wallet-a") == 96
     assert contracts.settlement.get_token_balance("node-wallet-b") == 192
     assert contracts.settlement.get_token_balance("validator-wallet") == 32
+
+
+def test_slash_proof_reduces_stake_increments_strikes_and_warns(capsys):
+    """Submitting a slash proof updates registry state and notifies the operator."""
+    contracts = LocalSolanaContracts()
+    contracts.registry.submit_stake("node-wallet-a", 500)
+
+    receipt = contracts.registry.submit_slash_proof(
+        wallet_address="node-wallet-a",
+        slash_amount=125,
+        strike_threshold=2,
+        reason="test divergence",
+    )
+
+    wallet = contracts.registry.get_wallet("node-wallet-a")
+    assert receipt.signature.startswith("local-slash-node-wallet-a")
+    assert wallet.stake_balance == 375
+    assert wallet.strike_count == 1
+    assert wallet.banned is False
+    assert "WARNING: node node-wallet-a slashed" in capsys.readouterr().out