fix: task delete → cancel (status=cancelled) instead of hard delete

Tasks now get status 'cancelled' when deleted — they remain in history.
Confirmation dialog updated to reflect this behaviour.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/TechnicalPage.tsx

@@ -90,10 +90,10 @@ export function TechnicalPage() {
   }
 
   const handleDelete = async (taskId: string) => {
-    if (!confirm('Удалить задачу?')) return
+    if (!confirm('Отменить задачу? Она останется в истории со статусом «Отменено».')) return
     try {
-      await api.housekeeping.delete(slug, taskId)
-      setTasks(prev => prev.filter(t => t.id !== taskId))
+      const updated = await api.housekeeping.update(slug, taskId, { status: 'cancelled' })
+      setTasks(prev => prev.map(t => t.id === taskId ? updated : t))
     } catch (err) {
       console.error(err)
     }