feat(protocol): AST compiler to (df -> Series[Side]) signal fn

Implementa compile_strategy che produce funzione df -> Series[Side]
con valutazione regole in ordine, prima-che-matcha vince, FLAT default
e NaN per warmup degli indicatori.

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

tests/unit/test_protocol_compiler.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+import numpy as np
+import pandas as pd
+import pytest
+
+from multi_swarm.backtest.orders import Side
+from multi_swarm.protocol.compiler import compile_strategy
+from multi_swarm.protocol.parser import parse_strategy
+
+
+@pytest.fixture
+def ohlcv() -> pd.DataFrame:
+    idx = pd.date_range("2024-01-01", periods=200, freq="1h", tz="UTC")
+    close = np.linspace(100, 120, 200)
+    return pd.DataFrame(
+        {
+            "open": close,
+            "high": close + 0.5,
+            "low": close - 0.5,
+            "close": close,
+            "volume": 1.0,
+        },
+        index=idx,
+    )
+
+
+def test_compile_simple_long(ohlcv: pd.DataFrame) -> None:
+    src = "(strategy (when (lt (indicator rsi 14) 100.0) (entry-long)))"
+    ast = parse_strategy(src)
+    fn = compile_strategy(ast)
+    signals = fn(ohlcv)
+    assert isinstance(signals, pd.Series)
+    assert (signals == Side.LONG).all() or (signals.dropna() == Side.LONG).all()
+
+
+def test_compile_no_match_is_flat(ohlcv: pd.DataFrame) -> None:
+    src = "(strategy (when (gt (indicator rsi 14) 1000.0) (entry-long)))"
+    ast = parse_strategy(src)
+    fn = compile_strategy(ast)
+    signals = fn(ohlcv)
+    assert (signals == Side.FLAT).any()
+
+
+def test_compile_two_rules_priority(ohlcv: pd.DataFrame) -> None:
+    src = """
+    (strategy
+      (when (gt (feature close) 110.0) (entry-long))
+      (when (lt (feature close) 105.0) (entry-short)))
+    """
+    ast = parse_strategy(src)
+    fn = compile_strategy(ast)
+    signals = fn(ohlcv)
+    last = signals.iloc[-1]
+    assert last == Side.LONG  # close finale e' 120, regola 1 matcha