First swing.

src/hooks/useInstanceContext.tsx

@@ -0,0 +1,37 @@
+import { useState, createContext, useContext, ReactNode } from 'react';
+
+interface InstanceContextValue {
+  currentInstance: string | null;
+  setCurrentInstance: (name: string | null) => void;
+}
+
+const InstanceContext = createContext<InstanceContextValue | undefined>(undefined);
+
+export function InstanceProvider({ children }: { children: ReactNode }) {
+  const [currentInstance, setCurrentInstanceState] = useState<string | null>(
+    () => localStorage.getItem('currentInstance')
+  );
+
+  const setCurrentInstance = (name: string | null) => {
+    setCurrentInstanceState(name);
+    if (name) {
+      localStorage.setItem('currentInstance', name);
+    } else {
+      localStorage.removeItem('currentInstance');
+    }
+  };
+
+  return (
+    <InstanceContext.Provider value={{ currentInstance, setCurrentInstance }}>
+      {children}
+    </InstanceContext.Provider>
+  );
+}
+
+export function useInstanceContext() {
+  const context = useContext(InstanceContext);
+  if (context === undefined) {
+    throw new Error('useInstanceContext must be used within an InstanceProvider');
+  }
+  return context;
+}