feat(backend): update collections, config and migration tools

Update Payload CMS configuration, collections (Audit, Posts), and add migration scripts/reports.

apps/backend/clean-package.js

@@ -0,0 +1,9 @@
+const fs = require('fs');
+const p = JSON.parse(fs.readFileSync('./package.json.orig', 'utf8'));
+delete p.devDependencies;
+delete p.engines;
+if (p.dependencies && p.dependencies['@enchun/shared']) {
+  p.dependencies['@enchun/shared'] = 'file:./shared';
+}
+fs.writeFileSync('./package.json', JSON.stringify(p, null, 2));
+fs.unlinkSync('./package.json.orig');