feat: YARA .yar 规则自动化生成 + 边界记录验证

rules/test_rules.yar (7 条规则):
  - Test_ReverseShell_Basic: nc 反弹 shell
  - Test_PowerShell_Download: Invoke-WebRequest
  - Newly_Added_Rule_Test: 热加载验证
  - Meta_Label_Test: metadata 输出验证
  - Regex_Shell_Pattern: powershell -enc 正则
  - Count_Condition_Test: count >= 3 条件
  - Size_Condition_Test: filesize <= 10KB 条件

YARA 命中验证: 7/7 ✅
  L4-001 → Test_ReverseShell_Basic + keywords.ReverseShellNetcat 复合命中
  L4-004 → Test_ReverseShell_Basic + Test_PowerShell_Download + 3 条关键词
  L4-005/007/010/011/012 → 全部命中 ✅

边界记录验证: 4/4 ✅ 全 clean
  L1-005 EICAR 1 字节修改 → ClamAV 不命中 ✅
  L1-012 EICAR base64 → ClamAV 不解码 ✅
  L3-007 高危串 base64 → 关键词不解码 ✅
  L3-019 unicode 同形字 → 关键词不还原 ✅

rules/test_rules.yar

@@ -0,0 +1,100 @@
+/* MeshSafe 测试靶场 YARA 规则
+ * 自动生成，覆盖 CSV L4-001 ~ L4-012
+ * 引擎自动扫描 rules/*.yar，热加载
+ */
+
+// L4-001: 基础规则 —— 正向命中 shell 反弹特征
+rule Test_ReverseShell_Basic {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        version = "1.0"
+        description = "L4-001 基础规则: 匹配 nc 反弹 shell 特征"
+    strings:
+        $a = /nc\s+[0-9.]+\s+[0-9]+\s+-e/
+        $b = /bash\s+-i\s+>&\s+\/dev\/tcp\//
+    condition:
+        $a or $b
+}
+
+// L4-004: 第二条规则 —— 同时命中验证
+rule Test_PowerShell_Download {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        description = "L4-004 多规则同时命中: 匹配 PowerShell 下载"
+    strings:
+        $c = /Invoke-WebRequest\s+-Uri/
+        $d = /powershell\s+-w\s+hidden/
+    condition:
+        $c or $d
+}
+
+// L4-005: 新增规则（热加载验证）
+rule Newly_Added_Rule_Test {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        description = "L4-005 热加载验证: 运行时新增此规则后应能命中"
+    strings:
+        $e = "meshsafe-hot-reload-test-string"
+    condition:
+        $e
+}
+
+// L4-007: metadata 标签测试
+rule Meta_Label_Test {
+    meta:
+        family = "Trojan.Generic"
+        author = "Security Researcher"
+        description = "L4-007 metadata 输出验证: 规则带完整 meta 字段"
+        severity = "high"
+    strings:
+        $f = "trojan-metadata-test"
+    condition:
+        $f
+}
+
+// L4-010: 正则型规则
+rule Regex_Shell_Pattern {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        description = "L4-010 正则匹配: powershell -enc 编码执行"
+    strings:
+        $g = /powershell\s+-e[nN][cC]\s+[A-Za-z0-9+\/]{20,}/
+    condition:
+        $g
+}
+
+// L4-011: count 条件（出现 ≥3 次才触发）
+rule Count_Condition_Test {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        description = "L4-011 count 条件: 文件内匹配串 ≥3 次命中"
+    strings:
+        $h = "malicious_token_count_test"
+    condition:
+        #h >= 3
+}
+
+// L4-012: size 条件（仅匹配 ≤10KB 的文件）
+rule Size_Condition_Test {
+    meta:
+        family = "TestRules"
+        author = "MeshSafe Test Suite"
+        description = "L4-012 size 条件: 仅匹配 size <= 10KB 的文件"
+    strings:
+        $i = "size_condition_test_payload"
+    condition:
+        $i and filesize <= 10KB
+}
+
+// L4-003: PE 内字符串（实际是 Test_PowerShell_Download 的 strings 也在 PE 里）
+// 已由 Test_PowerShell_Download 覆盖，因为 PE 里的 strings() 也会被 YARA 扫描
+
+// L4-009: 加密包内无法扫描（不是规则缺失，是 zipfile 跳过加密内容）
+// L4-013: 大文件 YARA —— 由 Test_ReverseShell_Basic 自动覆盖大文件扫描
+// L4-014: 开关测试 —— 由引擎 is_enabled() 控制
+// L4-015: 哈希白名单 —— 需在 policy.yaml 配置，不是 .yar 文件