Implement batch user retrieval in AdminController and update routes

- Added a new method `getUsers` in AdminController to handle batch retrieval of user information based on hashed IDs.
- Updated adminRouter to include a new route for batch user retrieval.
- Enhanced AdminService with a method to fetch user details by hashed IDs, ensuring proper access control.
- Updated localization files to include the new "username" field for user connections in both German and English.
- Modified ServicesStatusView to utilize the new batch user retrieval for displaying usernames alongside connection counts.

backend/controllers/adminController.js

@@ -27,6 +27,7 @@ class AdminController {
         // User administration
         this.searchUsers = this.searchUsers.bind(this);
         this.getUser = this.getUser.bind(this);
+        this.getUsers = this.getUsers.bind(this);
         this.updateUser = this.updateUser.bind(this);
 
         // Rights
@@ -74,6 +75,30 @@ class AdminController {
         }
     }
 
+    async getUsers(req, res) {
+        try {
+            const { userid: requester } = req.headers;
+            let { ids } = req.query;
+            if (!ids) {
+                return res.status(400).json({ error: 'ids query parameter is required' });
+            }
+            // Unterstütze sowohl Array-Format (ids[]=...) als auch komma-separierten String (ids=...)
+            let hashedIds;
+            if (Array.isArray(ids)) {
+                hashedIds = ids;
+            } else if (typeof ids === 'string') {
+                hashedIds = ids.split(',').map(id => id.trim()).filter(id => id.length > 0);
+            } else {
+                return res.status(400).json({ error: 'ids must be an array or comma-separated string' });
+            }
+            const result = await AdminService.getUsersByHashedIds(requester, hashedIds);
+            res.status(200).json(result);
+        } catch (error) {
+            const status = error.message === 'noaccess' ? 403 : 500;
+            res.status(status).json({ error: error.message });
+        }
+    }
+
     async updateUser(req, res) {
         try {
             const { userid: requester } = req.headers;