fix: propagate dynamic IPs/ports to service pages; add apply restart feedback

Service pages (Email, Calendar, Files) now read IPs and ports from the
config API instead of hardcoded 172.20.0.x constants:
- GET /api/config now includes service_ips (dns, vip_mail, vip_calendar,
  vip_files, vip_webdav) computed from ip_range via ip_utils
- Email.jsx: mailIp, dnsIp, imapPort, smtpPort, webmailPort from context
- Calendar.jsx: calendarIp, dnsIp, calendarPort from context
- Files.jsx: filesIp, webdavIp, webdavPort, filegatorPort from context

Apply button now shows restart progress:
- "Restarting containers — please wait…" spinner while polling /health
- "Containers restarted successfully" on success (clears after 4s)
- "Timed out" / error message if health doesn't come back in 45s

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

webui/src/App.jsx

@@ -164,9 +164,39 @@ function App() {
     };
   }, [checkHealth, checkPending]);
 
+  const [applyStatus, setApplyStatus] = useState(null); // null | 'restarting' | 'done' | 'timeout' | 'error'
+  const [applyError, setApplyError] = useState('');
+
   const handleApply = useCallback(async () => {
-    await cellAPI.applyPending();
+    setApplyError('');
+    try {
+      await cellAPI.applyPending();
+    } catch (err) {
+      setApplyStatus('error');
+      setApplyError(err?.response?.data?.error || 'Apply request failed');
+      setTimeout(() => setApplyStatus(null), 6000);
+      return;
+    }
     setPending({ needs_restart: false, changes: [] });
+    setApplyStatus('restarting');
+
+    // Poll health until API responds again (max 45 s; it may briefly drop if cell-api restarts)
+    const deadline = Date.now() + 45000;
+    while (Date.now() < deadline) {
+      await new Promise(r => setTimeout(r, 2000));
+      try {
+        await healthAPI.check();
+        setIsOnline(true);
+        setApplyStatus('done');
+        setTimeout(() => setApplyStatus(null), 4000);
+        return;
+      } catch {
+        setIsOnline(false);
+      }
+    }
+    setApplyStatus('timeout');
+    setApplyError('Containers may still be starting — check docker logs if services are unavailable');
+    setTimeout(() => setApplyStatus(null), 8000);
   }, []);
 
   const handleCancel = useCallback(async () => {
@@ -231,10 +261,31 @@ function App() {
                 </div>
               )}
 
-              {isOnline && pending.needs_restart && (
+              {isOnline && pending.needs_restart && !applyStatus && (
                 <PendingRestartBanner pending={pending} onApply={handleApply} onCancel={handleCancel} />
               )}
 
+              {applyStatus === 'restarting' && (
+                <div className="mb-6 bg-blue-50 border border-blue-200 rounded-lg p-4 flex items-center gap-3">
+                  <RefreshCw className="h-5 w-5 text-blue-500 animate-spin flex-shrink-0" />
+                  <span className="text-sm font-medium text-blue-800">Restarting containers — please wait…</span>
+                </div>
+              )}
+
+              {applyStatus === 'done' && (
+                <div className="mb-6 bg-green-50 border border-green-200 rounded-lg p-4 flex items-center gap-3">
+                  <span className="h-5 w-5 text-green-500 flex-shrink-0 text-lg leading-none">✓</span>
+                  <span className="text-sm font-medium text-green-800">Containers restarted successfully</span>
+                </div>
+              )}
+
+              {(applyStatus === 'timeout' || applyStatus === 'error') && (
+                <div className="mb-6 bg-danger-50 border border-danger-200 rounded-lg p-4 flex items-center gap-3">
+                  <AlertTriangle className="h-5 w-5 text-danger-500 flex-shrink-0" />
+                  <span className="text-sm font-medium text-danger-800">{applyError}</span>
+                </div>
+              )}
+
               <Routes>
                 <Route path="/" element={<Dashboard isOnline={isOnline} />} />
                 <Route path="/peers" element={<Peers />} />