fix: IMAP-Serveradresse dynamisch aus Backend laden

Hardcodierte 192.168.1.131 in settings/page.tsx ersetzt durch
dynamischen API-Call GET /api/system/info → {fqdn, imap_port}.
Fallback auf window.location.hostname wenn API nicht antwortet.

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

src/app/settings/page.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState } from "react";
+import { useEffect, useState } from "react";
 import { useAuth } from "@/hooks/useAuth";
 import { Navbar } from "@/components/navbar";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
@@ -23,6 +23,8 @@ import {
   getTOTPSetup,
   confirmTOTPSetup,
   disableTOTP,
+  getSystemInfo,
+  type SystemInfo,
 } from "@/lib/api";
 
 export default function SettingsPage() {
@@ -57,6 +59,28 @@ export default function SettingsPage() {
   const [disableError, setDisableError] = useState("");
   const [disableLoading, setDisableLoading] = useState(false);
 
+  // ── System info (FQDN + IMAP-Ports) ───────────────────────────────────
+  const [systemInfo, setSystemInfo] = useState<SystemInfo | null>(null);
+  const [systemInfoLoading, setSystemInfoLoading] = useState(true);
+
+  useEffect(() => {
+    let cancelled = false;
+    setSystemInfoLoading(true);
+    getSystemInfo()
+      .then((info) => {
+        if (!cancelled) setSystemInfo(info);
+      })
+      .catch(() => {
+        if (!cancelled) setSystemInfo(null);
+      })
+      .finally(() => {
+        if (!cancelled) setSystemInfoLoading(false);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
   // Initialize email from user data once available
   if (user && !emailInitialized) {
     setEmail(user.email || "");
@@ -488,19 +512,30 @@ export default function SettingsPage() {
                 <Server className="h-3.5 w-3.5" aria-hidden="true" />
                 Server
               </span>
-              <span className="font-mono">192.168.1.131</span>
+              <span className="font-mono">
+                {systemInfoLoading
+                  ? "Laden..."
+                  : systemInfo?.fqdn ||
+                    (typeof window !== "undefined"
+                      ? window.location.hostname
+                      : "")}
+              </span>
 
               <span className="text-muted-foreground flex items-center gap-1.5">
                 <Lock className="h-3.5 w-3.5" aria-hidden="true" />
                 IMAP-Port
               </span>
-              <span className="font-mono">9993 (SSL/TLS)</span>
+              <span className="font-mono">
+                {systemInfo?.imap_port ?? 9993} (SSL/TLS)
+              </span>
 
               <span className="text-muted-foreground flex items-center gap-1.5">
                 <Lock className="h-3.5 w-3.5" aria-hidden="true" />
                 Alternativ-Port
               </span>
-              <span className="font-mono">993 (SSL/TLS)</span>
+              <span className="font-mono">
+                {systemInfo?.imap_port_alt ?? 993} (SSL/TLS)
+              </span>
 
               <span className="text-muted-foreground flex items-center gap-1.5">
                 <Lock className="h-3.5 w-3.5" aria-hidden="true" />