feat(pl): 运费结算审批分流与车辆挂车号等 PL 能力完善

拆分运费审批/出款页面，补充结算发票附件与菜单 SQL，并同步前后端模型与车辆相关展示。

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/sql/20260628_pl_vehicle_trailer_no.sql

@@ -0,0 +1,32 @@
+-- =============================================================================
+-- 运输管理 · 车辆表增加挂车号
+-- 执行库：shanxia2.0 门户库（与 web-admin 同库）
+-- 说明：可重复执行；挂车号为车辆主数据属性，地磅/出入库仍使用 license_plate
+-- =============================================================================
+
+SET NAMES utf8mb4;
+
+SET @col_exists := (
+  SELECT COUNT(*)
+  FROM information_schema.COLUMNS
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'pl_vehicle'
+    AND COLUMN_NAME = 'trailer_no'
+);
+
+SET @ddl := IF(
+  @col_exists = 0,
+  'ALTER TABLE `pl_vehicle` ADD COLUMN `trailer_no` varchar(20) DEFAULT NULL COMMENT ''挂车号'' AFTER `license_plate`',
+  'SELECT ''trailer_no already exists'' AS message'
+);
+
+PREPARE stmt FROM @ddl;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
+
+SELECT COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE, COLUMN_COMMENT
+FROM information_schema.COLUMNS
+WHERE TABLE_SCHEMA = DATABASE()
+  AND TABLE_NAME = 'pl_vehicle'
+  AND COLUMN_NAME IN ('license_plate', 'trailer_no')
+ORDER BY ORDINAL_POSITION;