feat: mobilni responsivita, testy, klavesove zkratky, drag & drop, univerzalizace

- Mobile responsive CSS (touch targets 44px, iOS anti-zoom, reduced motion)
- Vitest setup s 39 testy (formatters, attendanceHelpers, useTableSort)
- Klavesove zkratky (Shift+? napoveda, Ctrl+S ulozit, navigace)
- Drag & drop pro polozky nabidek (@dnd-kit, SortableRow, useSortableList)
- Univerzalizace: odstraneni BOHA brandingu z UI, emailu, PDF
- Smazany nepotrebne soubory (deploy.sh, AUTH_SYSTEM.md, example_design, .htaccess)
- CORS konfigurovatelny pres env promennou

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

src/admin/components/SortableRow.jsx

@@ -0,0 +1,53 @@
+import { useSortable } from '@dnd-kit/sortable'
+import { CSS } from '@dnd-kit/utilities'
+
+export function DragHandle({ listeners, attributes }) {
+  return (
+    <button
+      type="button"
+      className="admin-drag-handle"
+      {...attributes}
+      {...listeners}
+      title="Přetáhnout"
+      aria-label="Přetáhnout pro změnu pořadí"
+    >
+      <svg width="14" height="14" viewBox="0 0 24 24" fill="currentColor">
+        <circle cx="9" cy="5" r="1.5" />
+        <circle cx="15" cy="5" r="1.5" />
+        <circle cx="9" cy="12" r="1.5" />
+        <circle cx="15" cy="12" r="1.5" />
+        <circle cx="9" cy="19" r="1.5" />
+        <circle cx="15" cy="19" r="1.5" />
+      </svg>
+    </button>
+  )
+}
+
+export default function SortableRow({ id, children, disabled }) {
+  const {
+    attributes,
+    listeners,
+    setNodeRef,
+    transform,
+    transition,
+    isDragging,
+  } = useSortable({ id, disabled })
+
+  const style = {
+    transform: CSS.Transform.toString(transform),
+    transition,
+    opacity: isDragging ? 0.5 : 1,
+    position: 'relative',
+    zIndex: isDragging ? 10 : undefined,
+    background: isDragging ? 'var(--bg-secondary)' : undefined,
+  }
+
+  return (
+    <tr ref={setNodeRef} style={style}>
+      {typeof children === 'function'
+        ? children({ attributes, listeners })
+        : children
+      }
+    </tr>
+  )
+}