Refactor code and improve internationalization support

- Updated import statements to remove invisible characters.
- Standardized comments to use a consistent hyphen format.
- Adjusted username validation error messages for consistency.
- Enhanced email sending functions to include language support.
- Added email internationalization configuration for dynamic translations.
- Updated calendar and federation routes to include language in user queries.
- Improved user feedback messages in German and English for clarity.

server/config/bbb.js

@@ -1,4 +1,4 @@
-import crypto from 'crypto';
+import crypto from 'crypto';
 import xml2js from 'xml2js';
 import { log, fmtDuration, fmtStatus, fmtMethod, fmtReturncode, sanitizeBBBParams } from './logger.js';
 
@@ -98,7 +98,7 @@ export async function createMeeting(room, logoutURL, loginURL = null, presentati
     params.lockSettingsLockOnJoin = 'true';
   }
 
-  // Build optional presentation XML body – escape URL to prevent XML injection
+  // Build optional presentation XML body - escape URL to prevent XML injection
   let xmlBody = null;
   if (presentationUrl) {
     const safeUrl = presentationUrl