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/characters.js

@@ -0,0 +1,21 @@
+const express = require('express');
+const router = express.Router();
+const charactersController = require('../controllers/charactersController.js');
+var basicAuth = require('express-basic-auth');
+
+router.use(basicAuth({
+    users: { 'admin': 'supersecret' },
+    unauthorizedResponse: {
+        message: "Sorry Wizard, can't let you in."
+    }
+}));
+
+router.get('/', charactersController.characters_list);
+router.post('/', charactersController.new_character);
+router.delete('/actions/deleteAll', charactersController.delete_all);
+router.get('/actions/reset', charactersController.reset);
+router.get('/:characterId', charactersController.specific_character);
+router.delete('/:characterId', charactersController.delete_character);
+router.put('/:characterId', charactersController.update_character);
+
+module.exports = router;