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

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

apps/backend/scripts/migration/inspect-transform.ts

@@ -0,0 +1,29 @@
+#!/usr/bin/env tsx
+import { config as dotenvConfig } from 'dotenv'
+dotenvConfig({ path: '.env' })
+
+import { parseWebflowCSV } from './csvParser'
+import { transformPosts } from './transformers'
+
+async function main() {
+  const data = await parseWebflowCSV('/Users/pukpuk/Dev/website-enchun-mgr/恩群數位行銷 - 行銷放大鏡集.csv')
+
+  const failPost = data.posts.find((p: any) => p.title.includes('一點都不難'))
+  const transformed = transformPosts([failPost])[0]
+
+  console.log('=== TRANSFORMED POST DATA ===')
+  console.log('title:', transformed.title)
+  console.log('slug:', transformed.slug)
+  console.log('publishedAt:', transformed.publishedAt)
+  console.log('status:', transformed.status)
+  console.log('excerpt:', transformed.excerpt?.substring(0, 100))
+  console.log('content type:', typeof transformed.content)
+  console.log('content length:', transformed.content?.length)
+
+  // Parse and check content
+  const contentParsed = JSON.parse(transformed.content)
+  console.log('content.root exists:', contentParsed.root !== undefined)
+  console.log('content.root.type:', contentParsed.root?.type)
+}
+
+main().catch(console.error)