feat(logging): implement centralized logging system and replace console errors with structured logs

feat(federation): add room sync and deletion notification endpoints for federated instances

fix(federation): handle room deletion and update settings during sync process

feat(federation): enhance FederatedRoomCard and FederatedRoomDetail components to display deleted rooms

i18n: add translations for room deletion messages in English and German

src/components/FederatedRoomCard.jsx

@@ -1,4 +1,4 @@
-import { Globe, Trash2, ExternalLink, Hash, Users, Video, VideoOff } from 'lucide-react';
+import { Globe, Trash2, ExternalLink, Hash, Users, Video, VideoOff, AlertTriangle } from 'lucide-react';
 import { useNavigate } from 'react-router-dom';
 import { useLanguage } from '../contexts/LanguageContext';
 import api from '../services/api';
@@ -8,8 +8,11 @@ export default function FederatedRoomCard({ room, onRemove }) {
   const { t } = useLanguage();
   const navigate = useNavigate();
 
+  const isDeleted = room.deleted === 1 || room.deleted === true;
+
   const handleJoin = (e) => {
     e.stopPropagation();
+    if (isDeleted) return;
     window.open(room.join_url, '_blank');
   };
 
@@ -28,7 +31,7 @@ export default function FederatedRoomCard({ room, onRemove }) {
   const recordingOn = room.allow_recording === 1 || room.allow_recording === true;
 
   return (
-    <div className="card-hover group p-5 cursor-pointer" onClick={() => navigate(`/federation/rooms/${room.id}`)}>
+    <div className={`card-hover group p-5 cursor-pointer ${isDeleted ? 'opacity-60' : ''}`} onClick={() => navigate(`/federation/rooms/${room.id}`)}>
       <div className="flex items-start justify-between mb-3">
         <div className="flex-1 min-w-0">
           <div className="flex items-center gap-2">
@@ -36,9 +39,16 @@ export default function FederatedRoomCard({ room, onRemove }) {
             <h3 className="text-base font-semibold text-th-text truncate group-hover:text-th-accent transition-colors">
               {room.room_name}
             </h3>
-            <span className="flex-shrink-0 px-2 py-0.5 bg-th-accent/15 text-th-accent rounded-full text-xs font-medium">
-              {t('federation.federated')}
-            </span>
+            {isDeleted ? (
+              <span className="flex-shrink-0 px-2 py-0.5 bg-red-500/15 text-red-500 rounded-full text-xs font-medium flex items-center gap-1">
+                <AlertTriangle size={10} />
+                {t('federation.roomDeleted')}
+              </span>
+            ) : (
+              <span className="flex-shrink-0 px-2 py-0.5 bg-th-accent/15 text-th-accent rounded-full text-xs font-medium">
+                {t('federation.federated')}
+              </span>
+            )}
           </div>
           <p className="text-sm text-th-text-s mt-0.5 truncate">
             {t('federation.from')}: <span className="font-medium">{room.from_user}</span>
@@ -79,17 +89,21 @@ export default function FederatedRoomCard({ room, onRemove }) {
       </div>
 
       {/* Read-only notice */}
-      <p className="text-xs text-th-text-s mb-4 italic">{t('federation.readOnlyNotice')}</p>
+      <p className="text-xs text-th-text-s mb-4 italic">
+        {isDeleted ? t('federation.roomDeletedNotice') : t('federation.readOnlyNotice')}
+      </p>
 
       {/* Actions */}
       <div className="flex items-center gap-2 pt-3 border-t border-th-border">
-        <button
-          onClick={handleJoin}
-          className="btn-primary text-xs py-1.5 px-3 flex-1"
-        >
-          <ExternalLink size={14} />
-          {t('federation.joinMeeting')}
-        </button>
+        {!isDeleted && (
+          <button
+            onClick={handleJoin}
+            className="btn-primary text-xs py-1.5 px-3 flex-1"
+          >
+            <ExternalLink size={14} />
+            {t('federation.joinMeeting')}
+          </button>
+        )}
         <button
           onClick={handleRemove}
           className="btn-ghost text-xs py-1.5 px-2 text-th-error hover:text-th-error"