Add Cortex Portal — web visualization for knowledge graph

Express API server wrapping existing store/graph core with REST endpoints
for nodes, edges, graph, and search. React + Vite portal with React Flow
for interactive graph visualization, Tailwind CSS styling, and full CRUD UI
(sidebar, node panel, add/link modals, search bar, toast notifications).

portal/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "cortex-portal",
+  "private": true,
+  "version": "1.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@tanstack/react-query": "^5.62.0",
+    "@xyflow/react": "^12.4.0",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
+  },
+  "devDependencies": {
+    "@tailwindcss/vite": "^4.0.0",
+    "@types/react": "^19.0.0",
+    "@types/react-dom": "^19.0.0",
+    "tailwindcss": "^4.0.0",
+    "typescript": "^5.9.0",
+    "vite": "^6.0.0",
+    "@vitejs/plugin-react": "^4.3.0"
+  }
+}