feat(protocol): semantic validator for AST

Aggiunge validatore semantico per AST Strategy: arity check su
verbi logici/comparatori/data, whitelist indicatori
(sma, rsi, atr, macd, realized_vol) e feature OHLCV.

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

tests/unit/test_protocol_validator.py

@@ -0,0 +1,38 @@
+import pytest
+
+from multi_swarm.protocol.parser import parse_strategy
+from multi_swarm.protocol.validator import ValidationError, validate_strategy
+
+
+def test_valid_strategy_passes() -> None:
+    src = "(strategy (when (gt (indicator rsi 14) 70.0) (entry-short)))"
+    ast = parse_strategy(src)
+    validate_strategy(ast)  # no exception
+
+
+def test_indicator_unknown_name_fails() -> None:
+    src = "(strategy (when (gt (indicator wibble 14) 70.0) (entry-short)))"
+    ast = parse_strategy(src)
+    with pytest.raises(ValidationError, match="unknown indicator"):
+        validate_strategy(ast)
+
+
+def test_indicator_wrong_arity_fails() -> None:
+    src = "(strategy (when (gt (indicator rsi) 70.0) (entry-short)))"
+    ast = parse_strategy(src)
+    with pytest.raises(ValidationError):
+        validate_strategy(ast)
+
+
+def test_comparator_wrong_arity_fails() -> None:
+    src = "(strategy (when (gt 1.0) (entry-long)))"
+    ast = parse_strategy(src)
+    with pytest.raises(ValidationError):
+        validate_strategy(ast)
+
+
+def test_feature_unknown_column_fails() -> None:
+    src = "(strategy (when (gt (feature wibble) 100.0) (entry-long)))"
+    ast = parse_strategy(src)
+    with pytest.raises(ValidationError, match="unknown feature"):
+        validate_strategy(ast)