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/pages/FederatedRoomDetail.jsx

@@ -2,7 +2,7 @@ import { useState, useEffect } from 'react';
 import { useParams, useNavigate } from 'react-router-dom';
 import {
   ArrowLeft, Globe, ExternalLink, Trash2, Hash, Users,
-  Video, VideoOff, Loader2, Link2,
+  Video, VideoOff, Loader2, Link2, AlertTriangle,
 } from 'lucide-react';
 import api from '../services/api';
 import { useLanguage } from '../contexts/LanguageContext';
@@ -66,6 +66,7 @@ export default function FederatedRoomDetail() {
   if (!room) return null;
 
   const recordingOn = room.allow_recording === 1 || room.allow_recording === true;
+  const isDeleted = room.deleted === 1 || room.deleted === true;
 
   return (
     <div className="max-w-3xl mx-auto">
@@ -78,19 +79,38 @@ export default function FederatedRoomDetail() {
         {t('federation.backToDashboard')}
       </button>
 
+      {/* Deleted banner */}
+      {isDeleted && (
+        <div className="card p-4 mb-4 border-red-500/30 bg-red-500/10">
+          <div className="flex items-center gap-3">
+            <AlertTriangle size={20} className="text-red-500 flex-shrink-0" />
+            <div>
+              <p className="text-sm font-semibold text-red-500">{t('federation.roomDeleted')}</p>
+              <p className="text-xs text-th-text-s mt-0.5">{t('federation.roomDeletedNotice')}</p>
+            </div>
+          </div>
+        </div>
+      )}
+
       {/* Header */}
       <div className="card p-6 mb-4">
         <div className="flex flex-col sm:flex-row sm:items-start sm:justify-between gap-4">
           <div className="flex items-start gap-3 min-w-0">
-            <div className="w-10 h-10 rounded-lg bg-th-accent/15 flex items-center justify-center flex-shrink-0 mt-0.5">
-              <Globe size={20} className="text-th-accent" />
+            <div className={`w-10 h-10 rounded-lg flex items-center justify-center flex-shrink-0 mt-0.5 ${isDeleted ? 'bg-red-500/15' : 'bg-th-accent/15'}`}>
+              {isDeleted ? <AlertTriangle size={20} className="text-red-500" /> : <Globe size={20} className="text-th-accent" />}
             </div>
             <div className="min-w-0">
               <div className="flex items-center gap-2 flex-wrap">
                 <h1 className="text-xl font-bold text-th-text truncate">{room.room_name}</h1>
-                <span className="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="px-2 py-0.5 bg-red-500/15 text-red-500 rounded-full text-xs font-medium">
+                    {t('federation.roomDeleted')}
+                  </span>
+                ) : (
+                  <span className="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-1">
                 {t('federation.from')}: <span className="font-medium text-th-text">{room.from_user}</span>
@@ -99,13 +119,15 @@ export default function FederatedRoomDetail() {
           </div>
 
           <div className="flex items-center gap-2 flex-shrink-0">
-            <button
-              onClick={handleJoin}
-              className="btn-primary"
-            >
-              <ExternalLink size={16} />
-              {t('federation.joinMeeting')}
-            </button>
+            {!isDeleted && (
+              <button
+                onClick={handleJoin}
+                className="btn-primary"
+              >
+                <ExternalLink size={16} />
+                {t('federation.joinMeeting')}
+              </button>
+            )}
             <button
               onClick={handleRemove}
               disabled={removing}
@@ -176,7 +198,7 @@ export default function FederatedRoomDetail() {
 
       {/* Read-only notice */}
       <p className="text-xs text-th-text-s mt-4 text-center italic">
-        {t('federation.readOnlyNotice')}
+        {isDeleted ? t('federation.roomDeletedNotice') : t('federation.readOnlyNotice')}
       </p>
     </div>
   );