fix: step3 _normalize_rule 将 table source 的 null row 转为 0 - Closes #73

LLM 输出 table source 时 row 字段可能为 null，导致 Layer A schema 失败。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

skills/ir_generation_skill/step3_merge_and_audit.py

@@ -206,7 +206,12 @@ def _normalize_rule(rule: dict) -> dict:
             if stype and stype not in valid_types:
                 src["type"] = "text"
                 stype = "text"
-            if stype in ("table", "text"):
+            if stype == "table":
+                if not src.get("section"):
+                    src["section"] = default_section
+                if src.get("row") is None:
+                    src["row"] = 0
+            elif stype == "text":
                 if not src.get("section"):
                     src["section"] = default_section
     else:

skills/ir_generation_skill/tests/test_step3.py

@@ -512,6 +512,18 @@ class TestNormalizeRule:
         normalized = _normalize_rule(rule)
         assert "section" not in normalized["sources"][0]
 
+
+    def test_normalize_table_source_null_row(self):
+        """Table source with null row gets row=0 (defensive)."""
+        rule = {
+            "trigger": {"conditions": [{"signal": "x", "operator": "==", "value": "1"}]},
+            "sources": [
+                {"type": "table", "section": "3.1 功能", "row": None},
+            ],
+        }
+        normalized = _normalize_rule(rule)
+        assert normalized["sources"][0]["row"] == 0
+
     def test_normalize_source_invalid_type(self):
         """Invalid source types (LLM hallucinations) are normalized to text."""
         rule = {