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/middleware/auth.js

@@ -0,0 +1,14 @@
+let jwt = require('jsonwebtoken');
+module.exports = checkToken;
+
+function checkToken(req, res, next) {
+    jwt.verify(req.token, 'secretkey', (err, authData) => {
+        if (err) {
+            res.status(403);
+            res.send(err);
+        } else {
+            next();
+        }
+    })
+}
+