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/settings.css

@@ -52,3 +52,13 @@
   line-height: 1.4;
   padding-left: 2.75rem;
 }
+
+@media (max-width: 768px) {
+  .admin-permission-item {
+    padding: 0.75rem;
+  }
+
+  .admin-permission-item .admin-form-checkbox {
+    min-height: 44px;
+  }
+}