feat: Kanban touch drag, admins delete backups, bigger share message

- Kanban on phones/tablets: hold a card, drag it onto a card or column, release; the page scrolls at the edges
- Admin settings: database backups can be deleted (DELETE /api/v1/admin/backups/{name})
- Share message: large Liste/Aufgabe buttons, close button, tap outside closes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/triage/TasksView.tsx

@@ -31,6 +31,7 @@ import {
 import { TaskList, Thought, SubTask, Team, User, TaskListMember, KanbanColumn, PriorityLevel, Recurrence, RECURRENCE_LABELS } from '../../lib/types';
 import { formatDue, isDueToday, isOverdue, localDay, splitDue } from '../../lib/due';
 import { readViewSession, writeViewSession } from '../../lib/viewSession';
+import { useKanbanTouchDrag } from './useKanbanTouchDrag';
 import { api, triggerHaptic } from '../../lib/api';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
 import { TaskDetailModal } from './TaskDetailModal';
@@ -807,7 +808,11 @@ export const TasksView: React.FC<TasksViewProps> = ({
     setDraggingTaskId(null);
     setDragOverTaskTarget(null);
     setDragOverKanbanCol(null);
+    await moveTaskNextTo(sourceId, targetTask, position, newKanbanCol);
+  };
 
+  // Shared by mouse drag & drop and the touch drag on the Kanban board
+  const moveTaskNextTo = async (sourceId: string | null, targetTask: Thought, position: 'before' | 'after', newKanbanCol?: string) => {
     if (!sourceId || sourceId === targetTask.id) return;
     triggerHaptic(15);
 
@@ -864,7 +869,10 @@ export const TasksView: React.FC<TasksViewProps> = ({
     setDraggingTaskId(null);
     setDragOverTaskTarget(null);
     setDragOverKanbanCol(null);
+    await moveTaskToColumn(sourceId, colId);
+  };
 
+  const moveTaskToColumn = async (sourceId: string | null, colId: string) => {
     if (!sourceId) return;
     triggerHaptic(15);
 
@@ -905,6 +913,28 @@ export const TasksView: React.FC<TasksViewProps> = ({
     }
   };
 
+  // Kanban with a finger: hold a card, drag it, let go (mouse and pen use HTML5 drag & drop)
+  const clearDragState = () => {
+    setDraggingTaskId(null);
+    setDragOverTaskTarget(null);
+    setDragOverKanbanCol(null);
+  };
+  const kanbanTouch = useKanbanTouchDrag({
+    enabled: !canDragTasks && viewMode === 'kanban',
+    onStart: (taskId) => setDraggingTaskId(taskId),
+    onHover: (colId, target) => {
+      setDragOverKanbanCol(colId);
+      setDragOverTaskTarget(target);
+    },
+    onDrop: (taskId, colId, target) => {
+      clearDragState();
+      const targetTask = target ? tasks.find((t) => t.id === target.taskId) : undefined;
+      if (targetTask && target) void moveTaskNextTo(taskId, targetTask, target.position, colId ?? undefined);
+      else if (colId) void moveTaskToColumn(taskId, colId);
+    },
+    onCancel: clearDragState,
+  });
+
   const handleCreateTaskList = async (e: React.FormEvent) => {
     e.preventDefault();
     const title = newListTitle.trim();
@@ -2224,6 +2254,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
       {viewMode === 'kanban' ? (
         /* DYNAMIC KANBAN BOARD */
         <div className="space-y-2">
+          {kanbanTouch.ghost}
           <div
             className={`grid grid-cols-1 md:grid-cols-2 gap-3 pt-1 lg:w-[var(--kanban-w)] lg:ml-[var(--kanban-ml)] transition-[width,margin] duration-300 ease-out ${
               isKanbanWide ? 'lg:grid-cols-[repeat(var(--kanban-cols),minmax(0,1fr))]' : 'lg:grid-cols-4'
@@ -2251,6 +2282,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
                     if (dragOverKanbanCol === col.id) setDragOverKanbanCol(null);
                   }}
                   onDrop={(e) => handleDropOnKanbanCol(e, col.id)}
+                  data-kanban-col={col.id}
                   className={`bg-canvas border border-border flex flex-col min-h-[420px] overflow-hidden transition-all ${
                     dragOverKanbanCol === col.id ? 'ring-2 ring-accent/60 bg-accent/5' : ''
                   }`}
@@ -2295,11 +2327,14 @@ export const TasksView: React.FC<TasksViewProps> = ({
                           onDragOver={(e) => handleTaskDragOver(e, task.id)}
                           onDragLeave={(e) => handleTaskDragLeave(e, task.id)}
                           onDrop={(e) => handleDropOnTask(e, task, col.id)}
+                          data-kanban-task={task.id}
+                          {...kanbanTouch.cardProps(task.id, task.content, !readOnly)}
                           onClick={() => {
+                            if (kanbanTouch.consumeClick()) return;
                             setDetailTaskId(task.id);
                             setShowDetailModal(true);
                           }}
-                          className={`panel-surface p-2.5 space-y-2 hover:border-strong transition-all shadow-sm group relative ${
+                          className={`panel-surface p-2.5 space-y-2 hover:border-strong transition-all shadow-sm group relative select-none ${
                             readOnly ? 'cursor-pointer' : 'cursor-grab active:cursor-grabbing'
                           } ${
                             isDragging ? 'opacity-30 border border-dashed border-accent/40' : ''