refactor: 合并 biz_support_unit/biz_execution_unit/biz_service_org 为 biz_org, 删除 2 张孤儿表, 改 biz_person.work_unit → org_id FK

主要改动:
- SQL: biz_support_unit → biz_org, 加 org_type, 加 business_nature; 删 biz_execution_unit, biz_service_org
- SQL: biz_project.support_unit_id/name + service_org_id/name → org_id/name/type
- SQL: biz_meeting.support_unit_name → org_name
- SQL: biz_person.work_unit → org_id (FK)
- 后端: 新 BizOrg entity/mapper/service/controller
- 后端: BizProject/BizMeeting 字段重命名
- 后端: 删 12 个 BizSupportUnit/BizExecutionUnit/BizServiceOrg Java 文件
- 后端: BizPersonImportVO.workUnit → orgName (导入时查 biz_org 取 org_id)
- 后端: BizAuthController.registerExecutor 完整实现 (原 registerSupplier stub)
- 前端: 新 admin/Orgs.vue + manager/Orgs.vue (原 SupportUnits)
- 前端: RegisterExecutor.vue (原 RegisterSupplier, 单页 2 步)
- 前端: sponsor/executor/manager 多个文件 workUnit → orgId/orgName 重命名
- 前端: 统一 supplier → executor, 业务命名 sponsor(赞助方) / executor(执行方=供应商)
- 前端: 全工程 execution → executor (company type / role / person unit_type)

ry-vue3/src/assets/main.scss

@@ -0,0 +1,7 @@
+html, body, #app { height: 100%; margin: 0; padding: 0; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif; }
+:root { --theme-color: #409eff; --theme-color-light: #66b1ff; --theme-color-dark: #3a8ee6; }
+.page-wrap { padding: 16px; }
+.page-card { background: #fff; border-radius: 6px; padding: 16px; box-shadow: 0 1px 4px rgba(0,21,41,.08); margin-bottom: 16px; }
+.page-title { font-size: 18px; font-weight: 600; margin-bottom: 12px; color: #1f1f1f; }
+.filter-bar { margin-bottom: 12px; }
+.toolbar { margin-bottom: 12px; display: flex; gap: 8px; }