refactor(manage): 收口部门负责人ID规范化逻辑并简化后端对话可见性校验

- 后端：任务群/项目群统一按项目级共享判断，不再区分任务可见性
- 前端：新增 department/owner/ids/save mutation 及 normalizeIntArray 工具函数
- 前端：departmentOwnerReadonlyUrls 从 action 局部变量提升至 state
- 前端：修复 TaskDetail 提示文本多余空格

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Models/WebSocketDialog.php

@@ -904,19 +904,16 @@ class WebSocketDialog extends AbstractModel
             case 'project':
             case 'task':
                 // 项目群、任务群对话校验是否在项目内
-                $taskVisibility = 1;    // 项目群不涉及任务可见性，按可见处理
                 if ($dialog->group_type === 'project') {
                     $projectId = intval(Project::whereDialogId($dialog->id)->value('id'));
                 } else {
-                    $taskRow = ProjectTask::select(['project_id', 'visibility'])->whereDialogId($dialog->id)->first();
-                    $projectId = intval($taskRow?->project_id);
-                    $taskVisibility = intval($taskRow?->visibility);
+                    $projectId = intval(ProjectTask::whereDialogId($dialog->id)->value('project_id'));
                 }
                 if ($projectId > 0 && ProjectUser::whereProjectId($projectId)->whereUserid($userid)->exists()) {
                     return $dialog;
                 }
-                // 部门负责人只读视角：项目群放行；任务群仅"全员可见"任务放行，指定成员可见任务不放行
-                if ($projectId > 0 && $checkOwner === false && ($dialog->group_type === 'project' || $taskVisibility === 1)) {
+                // 部门负责人只读视角：项目/任务群按项目级共享放行（任务数据另按可见性校验，与普通成员一致）
+                if ($projectId > 0 && $checkOwner === false) {
                     $departmentView = UserDepartment::ownerViewContext(User::auth(), true);
                     if (UserDepartment::isDepartmentReadonlyProject($departmentView, $projectId)) {
                         return $dialog;