feat(V2): migrazione hyperliquid completa

- exchanges/hyperliquid/{client,leverage_cap,tools}.py
- routers/hyperliquid.py con 16 endpoint /mcp-hyperliquid/tools/*
- builder hyperliquid in exchanges/__init__.py
- test migrati: test_client, test_leverage_cap (skip V1: server_acl, environment_info)
- test builder hyperliquid (testnet vs mainnet base_url)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/exchanges/hyperliquid/test_leverage_cap.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import pytest
+from fastapi import HTTPException
+from cerbero_mcp.exchanges.hyperliquid.leverage_cap import enforce_leverage, get_max_leverage
+
+
+def test_get_max_leverage_returns_creds_value():
+    creds = {"max_leverage": 5}
+    assert get_max_leverage(creds) == 5
+
+
+def test_get_max_leverage_default_when_missing():
+    """Default 1 (cash) se il secret non ha max_leverage."""
+    assert get_max_leverage({}) == 1
+
+
+def test_enforce_leverage_pass_under_cap():
+    creds = {"max_leverage": 3}
+    enforce_leverage(2, creds=creds, exchange="hyperliquid")  # no raise
+
+
+def test_enforce_leverage_pass_at_cap():
+    creds = {"max_leverage": 3}
+    enforce_leverage(3, creds=creds, exchange="hyperliquid")  # no raise
+
+
+def test_enforce_leverage_reject_over_cap():
+    creds = {"max_leverage": 3}
+    with pytest.raises(HTTPException) as exc:
+        enforce_leverage(10, creds=creds, exchange="hyperliquid")
+    assert exc.value.status_code == 403
+    assert exc.value.detail["error"] == "LEVERAGE_CAP_EXCEEDED"
+    assert exc.value.detail["exchange"] == "hyperliquid"
+    assert exc.value.detail["requested"] == 10
+    assert exc.value.detail["max"] == 3
+
+
+def test_enforce_leverage_reject_when_below_one():
+    creds = {"max_leverage": 3}
+    with pytest.raises(HTTPException) as exc:
+        enforce_leverage(0, creds=creds, exchange="hyperliquid")
+    assert exc.value.status_code == 403
+
+
+def test_enforce_leverage_default_when_none():
+    """Se requested è None, applica il cap come default."""
+    creds = {"max_leverage": 3}
+    result = enforce_leverage(None, creds=creds, exchange="hyperliquid")
+    assert result == 3