fix: remove remaining /api/ double-prefix from template literal API calls

Previous fix missed backtick template strings. Fixed 7 more api.*()
calls in appointments, deadlines, settings, and einstellungen pages.

frontend/src/app/(app)/einstellungen/page.tsx

@@ -22,7 +22,7 @@ export default function EinstellungenPage() {
     refetch,
   } = useQuery({
     queryKey: ["tenant-current", tenantId],
-    queryFn: () => api.get<Tenant>(`/api/tenants/${tenantId}`),
+    queryFn: () => api.get<Tenant>(`/tenants/${tenantId}`),
     enabled: !!tenantId,
   });
 

frontend/src/components/appointments/AppointmentModal.tsx

@@ -78,7 +78,7 @@ export function AppointmentModal({ open, onClose, appointment }: AppointmentModa
 
   const updateMutation = useMutation({
     mutationFn: (body: Record<string, unknown>) =>
-      api.put<Appointment>(`/api/appointments/${appointment!.id}`, body),
+      api.put<Appointment>(`/appointments/${appointment!.id}`, body),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["appointments"] });
       queryClient.invalidateQueries({ queryKey: ["dashboard"] });

frontend/src/components/deadlines/DeadlineList.tsx

@@ -64,7 +64,7 @@ export function DeadlineList() {
 
   const completeMutation = useMutation({
     mutationFn: (id: string) =>
-      api.patch<Deadline>(`/api/deadlines/${id}/complete`),
+      api.patch<Deadline>(`/deadlines/${id}/complete`),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["deadlines"] });
       toast.success("Frist als erledigt markiert");

frontend/src/components/settings/CalDAVSettings.tsx

@@ -68,7 +68,7 @@ export function CalDAVSettings({ tenant }: { tenant: Tenant }) {
         typeof window !== "undefined"
           ? localStorage.getItem("kanzlai_tenant_id")
           : null;
-      return api.put<Tenant>(`/api/tenants/${tenantId}/settings`, {
+      return api.put<Tenant>(`/tenants/${tenantId}/settings`, {
         caldav: cfg,
       });
     },

frontend/src/components/settings/TeamSettings.tsx

@@ -32,13 +32,13 @@ export function TeamSettings() {
   } = useQuery({
     queryKey: ["tenant-members", tenantId],
     queryFn: () =>
-      api.get<UserTenant[]>(`/api/tenants/${tenantId}/members`),
+      api.get<UserTenant[]>(`/tenants/${tenantId}/members`),
     enabled: !!tenantId,
   });
 
   const inviteMutation = useMutation({
     mutationFn: (data: { email: string; role: string }) =>
-      api.post(`/api/tenants/${tenantId}/invite`, data),
+      api.post(`/tenants/${tenantId}/invite`, data),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["tenant-members"] });
       setEmail("");
@@ -52,7 +52,7 @@ export function TeamSettings() {
 
   const removeMutation = useMutation({
     mutationFn: (userId: string) =>
-      api.delete(`/api/tenants/${tenantId}/members/${userId}`),
+      api.delete(`/tenants/${tenantId}/members/${userId}`),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["tenant-members"] });
       toast.success("Mitglied entfernt");