feat: Implement collaboration features including user following and avatar management

app/src/store/useCollabStore.ts

@@ -0,0 +1,30 @@
+import { create } from 'zustand';
+
+interface SelectedUser {
+    color: string;
+    name: string;
+    location?: {
+        position: {
+            x: number;
+            y: number;
+            z: number;
+        };
+        rotation: {
+            x: number;
+            y: number;
+            z: number;
+        };
+    }
+}
+
+interface SelectedUserStore {
+    selectedUser: SelectedUser | null;
+    setSelectedUser: (user: SelectedUser) => void;
+    clearSelectedUser: () => void;
+}
+
+export const useSelectedUserStore = create<SelectedUserStore>((set) => ({
+    selectedUser: null,
+    setSelectedUser: (user) => set({ selectedUser: user }),
+    clearSelectedUser: () => set({ selectedUser: null }),
+}));