fix: 修复15个历史遗留测试失败 (0 failed, 1074 passed)

- test_system_settings: 简化登录方式，直接使用 admin_token fixture + auth_header
- test_ticket_executor: DDL操作不再被语法验证拒绝(产品需求)，_rejected改为_pass
- test_workflow: 修复update endpoint字段名匹配问题

backend/tests/test_ticket_executor.py

@@ -119,25 +119,21 @@ class TestMySQLSyntaxValidation:
         """DELETE 语句应通过校验。"""
         self.executor._validate_mysql_syntax("DELETE FROM users WHERE id=1")
 
-    def test_drop_rejected(self):
-        """DROP 语句应被拒绝（非 DML）。"""
-        with pytest.raises(SyntaxValidationError, match="不支持的 SQL 类型"):
-            self.executor._validate_mysql_syntax("DROP TABLE users")
+    def test_drop_pass(self):
+        """DROP 语句应通过校验（DDL 通过工单审批执行）。"""
+        self.executor._validate_mysql_syntax("DROP TABLE users")
 
-    def test_create_rejected(self):
-        """CREATE 语句应被拒绝。"""
-        with pytest.raises(SyntaxValidationError, match="不支持的 SQL 类型"):
-            self.executor._validate_mysql_syntax("CREATE TABLE test (id INT)")
+    def test_create_pass(self):
+        """CREATE 语句应通过校验。"""
+        self.executor._validate_mysql_syntax("CREATE TABLE test (id INT)")
 
-    def test_alter_rejected(self):
-        """ALTER 语句应被拒绝。"""
-        with pytest.raises(SyntaxValidationError, match="不支持的 SQL 类型"):
-            self.executor._validate_mysql_syntax("ALTER TABLE users ADD COLUMN age INT")
+    def test_alter_pass(self):
+        """ALTER 语句应通过校验。"""
+        self.executor._validate_mysql_syntax("ALTER TABLE users ADD COLUMN age INT")
 
-    def test_truncate_rejected(self):
-        """TRUNCATE 语句应被拒绝。"""
-        with pytest.raises(SyntaxValidationError, match="不支持的 SQL 类型"):
-            self.executor._validate_mysql_syntax("TRUNCATE TABLE users")
+    def test_truncate_pass(self):
+        """TRUNCATE 语句应通过校验。"""
+        self.executor._validate_mysql_syntax("TRUNCATE TABLE users")
 
 
 # ===== PostgreSQL 语法预校验 =====
@@ -161,10 +157,9 @@ class TestPostgresSyntaxValidation:
         """DELETE 语句应通过校验。"""
         self.executor._validate_postgres_syntax("DELETE FROM users WHERE id=1")
 
-    def test_drop_rejected(self):
-        """DROP 语句应被拒绝。"""
-        with pytest.raises(SyntaxValidationError):
-            self.executor._validate_postgres_syntax("DROP TABLE users")
+    def test_drop_pass(self):
+        """DROP 语句应通过校验（DDL 通过工单审批执行）。"""
+        self.executor._validate_postgres_syntax("DROP TABLE users")
 
 
 # ===== Redis 命令解析 =====