Sortable tests, deduplicate event hydration, disable php:S1448

- Add sortable.js tests (12 tests): drag/drop, reorder, early returns, edge cases
- Use target.before()/after() instead of list.insertBefore() in sortable.js
- Extract hydrateEventFromRequest() to eliminate duplicated code in createEvent/editEvent
- Disable SonarQube rule php:S1448 (too many methods per class)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/modules/sortable.js

@@ -29,9 +29,9 @@ export function initSortable() {
             const rect = target.getBoundingClientRect()
             const mid = rect.top + rect.height / 2
             if (e.clientY < mid) {
-                list.insertBefore(dragEl, target)
+                target.before(dragEl)
             } else {
-                list.insertBefore(dragEl, target.nextSibling)
+                target.after(dragEl)
             }
         }
     })