Add setup and restore flow

frontend/src/api.ts

@@ -89,6 +89,24 @@ export function updateCurrentUser(payload: {
   });
 }
 
+export function getSetupStatus() {
+  return request<{ required: boolean }>("/api/setup/status");
+}
+
+export function createSetupAdmin(payload: { username: string; displayName: string; password: string }) {
+  return request<{ user: AuthUser }>("/api/setup/admin", {
+    method: "POST",
+    body: JSON.stringify(payload)
+  });
+}
+
+export function restoreSetupBackup(sql: string) {
+  return request<{ ok: boolean }>("/api/setup/restore", {
+    method: "POST",
+    body: JSON.stringify({ sql })
+  });
+}
+
 export function getAdminUsers() {
   return request<{ users: AdminUser[] }>("/api/admin/users");
 }
@@ -139,6 +157,13 @@ export async function downloadDatabaseExport() {
   };
 }
 
+export function restoreDatabaseBackup(sql: string) {
+  return request<{ ok: boolean }>("/api/admin/restore/database", {
+    method: "POST",
+    body: JSON.stringify({ sql })
+  });
+}
+
 export async function downloadMonthExport(month: string) {
   const response = await fetch(`/api/export/months/${month}`, {
     credentials: "same-origin"