feat(scrap): 报废审批流 DB 迁移（建表 + 权限码）

- scrap_approval 表（申请单，items_json 携带 source_table+stock_id 精准实物）
- trans_scrap 增加 scrap_request_no 关联申请单
- 注册权限码 scrap_apply / scrap_approval / scrap_execute 并按现有报废角色授予

db_migrations/add_scrap_approval.sql

@@ -0,0 +1,31 @@
+-- =============================================================================
+-- 报废审批流 + 按单报废（镜像 借库/出库 审批框架）
+--   1) 新表 scrap_approval（申请单）
+--   2) trans_scrap 增加 scrap_request_no，关联申请单号
+-- 执行: docker exec -i inventory_db psql -U test -d inventory_system < 本文件
+-- =============================================================================
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS scrap_approval (
+  id                  SERIAL PRIMARY KEY,
+  request_no          varchar(100) UNIQUE NOT NULL,
+  applicant_id        integer NOT NULL,
+  remark              text,
+  status              integer NOT NULL DEFAULT 0,   -- 0待审 1已通过(待执行) 2驳回 3已执行
+  allowed_approvers   text,
+  actual_approver_id  integer,
+  approved_at         timestamptz,
+  reject_reason       text,
+  items_json          text NOT NULL,
+  executed_at         timestamptz,
+  executor_name       varchar(100),
+  created_at          timestamptz NOT NULL DEFAULT now(),
+  updated_at          timestamptz NOT NULL DEFAULT now()
+);
+CREATE INDEX IF NOT EXISTS ix_scrap_approval_status  ON scrap_approval(status);
+CREATE INDEX IF NOT EXISTS ix_scrap_approval_applicant ON scrap_approval(applicant_id);
+
+ALTER TABLE trans_scrap ADD COLUMN IF NOT EXISTS scrap_request_no varchar(100);
+CREATE INDEX IF NOT EXISTS ix_trans_scrap_req_no ON trans_scrap(scrap_request_no);
+
+COMMIT;

db_migrations/add_scrap_perm.sql

@@ -0,0 +1,57 @@
+-- =============================================================================
+-- 报废审批流权限码（动态权限，不硬编码角色）
+--   scrap_apply    提交报废申请 / 预检
+--   scrap_approval 查看审批列表 / 审批(通过/驳回)
+--   scrap_execute  按单报废执行(扣减库存)
+-- 授予：apply/execute 复制现有持 'scrap_create:operation' 的角色；
+--       approval 复制现有持 'scrap_list:operation' 的角色 + 超管/主管。
+-- 执行: docker exec -i inventory_db psql -U test -d inventory_system < 本文件
+-- =============================================================================
+BEGIN;
+
+-- 1) 注册权限元素
+INSERT INTO sys_element (menu_code, name, code, element_type)
+SELECT 'scrap_create', '报废申请(提交)', 'scrap_apply', 'operation'
+WHERE NOT EXISTS (SELECT 1 FROM sys_element WHERE code = 'scrap_apply');
+
+INSERT INTO sys_element (menu_code, name, code, element_type)
+SELECT 'scrap_create', '按单报废(执行)', 'scrap_execute', 'operation'
+WHERE NOT EXISTS (SELECT 1 FROM sys_element WHERE code = 'scrap_execute');
+
+INSERT INTO sys_element (menu_code, name, code, element_type)
+SELECT 'scrap_list', '报废审批(查看/审批)', 'scrap_approval', 'operation'
+WHERE NOT EXISTS (SELECT 1 FROM sys_element WHERE code = 'scrap_approval');
+
+-- 2) scrap_apply / scrap_execute ← 现有持 scrap_create:operation 的角色
+INSERT INTO sys_role_permission (role_code, target_code, type, company_name)
+SELECT DISTINCT sp.role_code, v.target_code, 'element', sp.company_name
+FROM sys_role_permission sp
+CROSS JOIN (VALUES ('scrap_apply'), ('scrap_execute')) AS v(target_code)
+WHERE sp.target_code = 'scrap_create:operation' AND sp.type = 'element'
+  AND NOT EXISTS (
+      SELECT 1 FROM sys_role_permission r
+      WHERE r.role_code = sp.role_code AND r.target_code = v.target_code
+        AND r.type = 'element' AND COALESCE(r.company_name,'') = COALESCE(sp.company_name,'')
+  );
+
+-- 3) scrap_approval ← 现有持 scrap_list:operation 的角色
+INSERT INTO sys_role_permission (role_code, target_code, type, company_name)
+SELECT DISTINCT sp.role_code, 'scrap_approval', 'element', sp.company_name
+FROM sys_role_permission sp
+WHERE sp.target_code = 'scrap_list:operation' AND sp.type = 'element'
+  AND NOT EXISTS (
+      SELECT 1 FROM sys_role_permission r
+      WHERE r.role_code = sp.role_code AND r.target_code = 'scrap_approval'
+        AND r.type = 'element' AND COALESCE(r.company_name,'') = COALESCE(sp.company_name,'')
+  );
+
+-- 4) 超管 / 主管 兜底持有审批权
+INSERT INTO sys_role_permission (role_code, target_code, type, company_name)
+SELECT v.role_code, 'scrap_approval', 'element', NULL
+FROM (VALUES ('SUPER_ADMIN'), ('SUPERVISOR')) AS v(role_code)
+WHERE NOT EXISTS (
+    SELECT 1 FROM sys_role_permission r
+    WHERE r.role_code = v.role_code AND r.target_code = 'scrap_approval' AND r.type = 'element'
+);
+
+COMMIT;