feat(detector): 扩展空字段检测到 L2 event_description / L1 scene_summary

断点续跑判据需要 L2/L1 层的 empty_field 检测。零 LLM 成本。

tests/unit/test_repair_detector.py

@@ -14,7 +14,7 @@ from app.tree.index import (
     L3Node,
     TreeIndex,
 )
-from app.tree.repair.detector import detect_issues
+from app.tree.repair.detector import NodeIssue, detect_issues
 
 if TYPE_CHECKING:
     from pathlib import Path
@@ -185,3 +185,53 @@ class TestDetectIssues:
         index = TreeIndex(metadata=IndexMeta("/t.mp4", "video"), roots=[l1])
         issues = detect_issues(index)
         assert any(i.issue_type == "time_gap" for i in issues)
+
+    def test_detects_l2_empty_event_description(self) -> None:
+        """L2 event_description 为空应报 empty_field。"""
+        l3 = L3Node(
+            id="l1_0_l2_0_l3_0",
+            card=L3Card("正常帧", ["实体"], ["动作"], [], "居中", {}),
+            timestamp=1.0,
+        )
+        l2 = L2Node(
+            id="l1_0_l2_0",
+            card=L2Card("", [], [], [], [], "", None),
+            time_range=(0.0, 10.0),
+            children=[l3],
+        )
+        l1 = L1Node(
+            id="l1_0",
+            card=L1Card("正常场景", "", [], [], [], [], ""),
+            time_range=(0.0, 10.0),
+            children=[l2],
+        )
+        index = TreeIndex(metadata=IndexMeta("/t.mp4", "video"), roots=[l1])
+        issues = detect_issues(index)
+        l2_empties = [i for i in issues if i.level == 2 and i.issue_type == "empty_field"]
+        assert len(l2_empties) == 1
+        assert "event_description" in l2_empties[0].details
+
+    def test_detects_l1_empty_scene_summary(self) -> None:
+        """L1 scene_summary 为空应报 empty_field。"""
+        l3 = L3Node(
+            id="l1_0_l2_0_l3_0",
+            card=L3Card("正常帧", ["实体"], ["动作"], [], "居中", {}),
+            timestamp=1.0,
+        )
+        l2 = L2Node(
+            id="l1_0_l2_0",
+            card=L2Card("正常事件", [], [], [], [], "", None),
+            time_range=(0.0, 10.0),
+            children=[l3],
+        )
+        l1 = L1Node(
+            id="l1_0",
+            card=L1Card("", "", [], [], [], [], ""),
+            time_range=(0.0, 10.0),
+            children=[l2],
+        )
+        index = TreeIndex(metadata=IndexMeta("/t.mp4", "video"), roots=[l1])
+        issues = detect_issues(index)
+        l1_empties = [i for i in issues if i.level == 1 and i.issue_type == "empty_field"]
+        assert len(l1_empties) == 1
+        assert "scene_summary" in l1_empties[0].details