fix: instance detail crash — use safe accessors for events/license (null check)

Root cause: useFetch returns the full API response { instance: {...} } but
the code assigned it directly: const instance = data
This meant instance.events and instance.license were undefined (data.events
doesn't exist, data.instance.events does).

Fix:
- const events = instance?.events ?? []
- const license = instance?.license ?? null
- Replaced all instance.events → events
- Replaced all instance.license → license
- format.ts already had null-safe date functions

src/components/aos/views/instances.tsx

@@ -631,6 +631,10 @@ function InstanceDetailSheet({
   const status = instance?.status ?? ''
   const fullDomain = instance ? `${instance.subdomain}.dfmpanel.eu` : ''
 
+  // Safe accessors — events and license may be undefined during loading
+  const events = instance?.events ?? []
+  const license = instance?.license ?? null
+
   return (
     <Sheet open={open} onOpenChange={onOpenChange}>
       <SheetContent
@@ -735,7 +739,7 @@ function InstanceDetailSheet({
               </section>
 
               {/* License info */}
-              {instance.license && (
+              {license && (
                 <section className="space-y-2">
                   <h3 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
                     Lizenz
@@ -745,20 +749,20 @@ function InstanceDetailSheet({
                       label="Key"
                       value={
                         <code className="text-xs">
-                          {maskLicenseKey(instance.license.key)}
+                          {maskLicenseKey(license.key)}
                         </code>
                       }
                     />
-                    <DetailRow label="Produkt" value={instance.license.product} />
+                    <DetailRow label="Produkt" value={license.product} />
                     <DetailRow
                       label="Abrechnung"
                       value={
-                        instance.license.billingCycle === 'yearly' ? 'Jährlich' : 'Monatlich'
+                        license.billingCycle === 'yearly' ? 'Jährlich' : 'Monatlich'
                       }
                     />
                     <DetailRow
                       label="Nettopreis"
-                      value={`${(instance.license.netPriceCents / 100).toLocaleString('de-DE', {
+                      value={`${(license.netPriceCents / 100).toLocaleString('de-DE', {
                         minimumFractionDigits: 2,
                         maximumFractionDigits: 2,
                       })} €`}
@@ -767,15 +771,15 @@ function InstanceDetailSheet({
                       label="Lizenzstatus"
                       value={
                         <Badge variant="outline" className="border-foreground/20">
-                          {instance.license.status}
+                          {license.status}
                         </Badge>
                       }
                     />
                     <DetailRow
                       label="Gekündigt"
                       value={
-                        instance.license.cancelledAt
-                          ? formatDate(instance.license.cancelledAt)
+                        license.cancelledAt
+                          ? formatDate(license.cancelledAt)
                           : '—'
                       }
                     />
@@ -819,7 +823,7 @@ function InstanceDetailSheet({
                 </h3>
                 <div className="rounded-md border border-border bg-muted/20 p-3 text-xs">
                   {(() => {
-                    const graphEvents = instance.events.filter(
+                    const graphEvents = events.filter(
                       (e) => e.type.startsWith('graphify.')
                     )
                     const buildQueued = graphEvents.some(
@@ -874,11 +878,11 @@ function InstanceDetailSheet({
                 <h3 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
                   Ereignisverlauf
                 </h3>
-                {instance.events.length === 0 ? (
+                {events.length === 0 ? (
                   <p className="text-xs text-muted-foreground">Keine Ereignisse protokolliert.</p>
                 ) : (
                   <ol className="space-y-2">
-                    {instance.events.map((ev) => (
+                    {events.map((ev) => (
                       <EventRow key={ev.id} event={ev} />
                     ))}
                   </ol>