chore: 将后端移动到 api/ 目录，准备合并为单仓库

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

api/static/admin/js/vendor/select2/i18n/eu.js

@@ -0,0 +1,3 @@
+/*! Select2 4.0.13 | https://github.com/select2/select2/blob/master/LICENSE.md */
+
+!function(){if(jQuery&&jQuery.fn&&jQuery.fn.select2&&jQuery.fn.select2.amd)var e=jQuery.fn.select2.amd;e.define("select2/i18n/eu",[],function(){return{inputTooLong:function(e){var t=e.input.length-e.maximum,n="Idatzi ";return n+=1==t?"karaktere bat":t+" karaktere",n+=" gutxiago"},inputTooShort:function(e){var t=e.minimum-e.input.length,n="Idatzi ";return n+=1==t?"karaktere bat":t+" karaktere",n+=" gehiago"},loadingMore:function(){return"Emaitza gehiago kargatzen…"},maximumSelected:function(e){return 1===e.maximum?"Elementu bakarra hauta dezakezu":e.maximum+" elementu hauta ditzakezu soilik"},noResults:function(){return"Ez da bat datorrenik aurkitu"},searching:function(){return"Bilatzen…"},removeAllItems:function(){return"Kendu elementu guztiak"}}}),e.define,e.require}();