Add German localization and styling for administration module

- Introduced new JavaScript file `fis.admin_txt_de.js` for German translations of administration-related terms and messages.
- Created `fis.admin.css` for styling the administration interface, including layout, cards, and buttons.
- Added `fis.admin.de.js` for the main functionality of the administration module, implementing features such as system status checks and email testing.
- Minified version of the German JavaScript file created as `fis.admin.de.min.js`.
- Minified CSS file created as `fis.admin.min.css` for optimized loading.

Fuchs/wwwroot/web/fis.js

@@ -2842,6 +2842,7 @@ $.extend($t, {
     , m_rep: 'Berichte'
     , m_todo: 'ToDos'
     , m_bcd: 'BankBuchungen'
+    , m_admin: 'Administration'
     , rsp: 'Passwort ändern'
     , pnm: 'Die Passwörter stimmen nicht überein'
     , cps: 'Das neue Passwort wurde gespeichert.'
@@ -3221,8 +3222,26 @@ $fis.draft = {
         //, { lbl: $t.m_efa, id: 'm_efa', fnc: 'init:efa' }
     ]);
 })();
+
+/* The Administration module is restricted to users whose fds_sys authorization exceeds 4.
+   The button is added — and only then does clicking it load the module script — after the
+   asynchronous auth check resolves, so lower-privileged users never see it or fetch the code.
+   Called from fis_main_go.js once the DOM (and the initial main menu) is ready. */
+$fis.addAdminMenuIfAuthorized = function () {
+    if ($('#m_admin').length > 0) { return; }   // idempotent
+    $fis.getAuth('fds_sys').then(function (auth) {
+        if ((auth || -1) > 4 && $('#m_admin').length === 0) {
+            $ocms.ocmsmenu.push({ lbl: $t.m_admin, id: 'm_admin', fnc: 'init:admin', ico: 'glyphicon glyphicon-cog' });
+            /* Re-render the main menu cleanly: drop the previously generated menu list
+               (never the .nav-right settings dropdown) and rebuild it from the array. */
+            $('#mainmenu').children('ul:not(.nav-right)').remove();
+            $('#mainmenu').ocmsmenu($ocms.ocmsmenu);
+        }
+    }).catch(function () { /* auth lookup failed → leave the menu unchanged */ });
+};
 $(document).ready(function () {
     $fis.notifications.init();
     $fis.draft.init();
     $fis.ov();
+    $fis.addAdminMenuIfAuthorized();
 });