Add nested Lambda scanner bypass PoCs

lambda_structure_compare.json

@@ -0,0 +1,20 @@
+[
+  {
+    "file": "tmp_poc/top_lambda_exec.keras",
+    "top_layers": [
+      "InputLayer",
+      "Lambda"
+    ],
+    "top_has_lambda": true,
+    "recursive_lambda_count": 1
+  },
+  {
+    "file": "tmp_poc/nested_lambda_exec.keras",
+    "top_layers": [
+      "InputLayer",
+      "Functional"
+    ],
+    "top_has_lambda": false,
+    "recursive_lambda_count": 1
+  }
+]

nested_lambda_exec_scan.json

@@ -0,0 +1 @@
+{"summary": {"total_issues_by_severity": {"LOW": 0, "MEDIUM": 0, "HIGH": 0, "CRITICAL": 0}, "total_issues": 0, "input_path": "tmp_poc/nested_lambda_exec.keras", "absolute_path": "D:\\repos\\safetensors\\tmp_poc", "modelscan_version": "0.8.8", "timestamp": "2026-03-22T07:01:22.649586", "scanned": {"total_scanned": 1, "scanned_files": ["nested_lambda_exec.keras"]}}, "issues": [], "errors": []}

top_lambda_exec_scan.json

@@ -0,0 +1 @@
+{"summary": {"total_issues_by_severity": {"LOW": 0, "MEDIUM": 1, "HIGH": 0, "CRITICAL": 0}, "total_issues": 1, "input_path": "tmp_poc/top_lambda_exec.keras", "absolute_path": "D:\\repos\\safetensors\\tmp_poc", "modelscan_version": "0.8.8", "timestamp": "2026-03-22T08:08:52.666404", "scanned": {"total_scanned": 1, "scanned_files": ["top_lambda_exec.keras"]}}, "issues": [{"description": "Use of unsafe operator 'Lambda' from module 'Keras'", "operator": "Lambda", "module": "Keras", "source": "top_lambda_exec.keras:config.json", "scanner": "modelscan.scanners.KerasLambdaDetectScan", "severity": "MEDIUM"}], "errors": []}