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/routes/quote.js

@@ -0,0 +1,12 @@
+const express = require('express');
+const router = express.Router();
+module.exports = router;
+const quotes = require('../quotes.json')
+
+function getRandomQuote() {
+    return quotes[Math.floor(Math.random() * quotes.length)];
+}
+
+router.get('/', function (req, res) {
+    res.json(getRandomQuote())
+});