Remove obsolete scripts and files, update site builder configurations

- Deleted the `import_plans.py`, `run_tests.py`, and `test_run.py` scripts as they are no longer needed.
- Updated the initial migration dependency in `0001_initial.py` to reflect recent changes in the `igny8_core_auth` app.
- Enhanced the implementation plan documentation to include new phases and updates on the site builder project.
- Updated the `vite.config.ts` and `package.json` to integrate testing configurations and dependencies for the site builder.

site-builder/src/setupTests.ts

@@ -0,0 +1,9 @@
+import { expect, afterEach } from 'vitest';
+import { cleanup } from '@testing-library/react';
+import '@testing-library/jest-dom/vitest';
+
+// Cleanup after each test
+afterEach(() => {
+  cleanup();
+});
+