refactor: restructure to monorepo with backends and apiTest

- Move web/backend to backends/potter-api
- Move web/frontend to backends/potter-api/frontend
- Add root package.json with npm workspaces
- Update README.md with monorepo navigation
- Update .github/workflows/api-tests.yml for dynamic test discovery
- Update bruno_test_scenario.md paths
- Fix .gitignore to allow JSON data files
- Add three new AI tests in apiTest/PotterAPI/AI/

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

backends/potter-api/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "PotterApi",
+  "version": "1.0.0",
+  "description": "",
+  "main": "app.js",
+  "scripts": {
+    "start": "nodemon app.js"
+  },
+  "engines": {
+    "node": "18.x"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^4.17.1",
+    "express-basic-auth": "^1.2.0",
+    "express-query-boolean": "^2.0.0",
+    "joi": "^17.6.0",
+    "jsonwebtoken": "^8.5.1",
+    "nodemon": "^2.0.2",
+    "random-id": "^1.0.3"
+  }
+}