Upgrade Asset Manager and Inbox; load Resend templates in Broadcast; v2.5.0

- Asset Manager: search/filter/sort, list+grid views, rename, move between R2 folders, tag chips, bulk actions, used-in counts; fix R2 delete lookup
- Inbox: readable wrapped rows with subject/preview, real read state, type filters, bulk actions, mojibake repair
- Broadcast: pick a Resend template to fill subject and body

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/r2.js

@@ -1,4 +1,4 @@
-import { S3Client, PutObjectCommand, DeleteObjectCommand, ListObjectsV2Command } from '@aws-sdk/client-s3'
+import { S3Client, PutObjectCommand, DeleteObjectCommand, CopyObjectCommand, ListObjectsV2Command } from '@aws-sdk/client-s3'
 import { R2_ACCOUNT_ID, R2_ACCESS_KEY_ID, R2_SECRET_ACCESS_KEY, R2_BUCKET, R2_PUBLIC_URL } from './config.js'
 
 function makeClient() {
@@ -27,6 +27,15 @@ export async function deleteFromR2(key) {
   await makeClient().send(new DeleteObjectCommand({ Bucket: R2_BUCKET, Key: key }))
 }
 
+export async function copyInR2(fromKey, toKey) {
+  await makeClient().send(new CopyObjectCommand({
+    Bucket: R2_BUCKET,
+    CopySource: `${R2_BUCKET}/${fromKey.split('/').map(encodeURIComponent).join('/')}`,
+    Key: toKey,
+  }))
+  return `${R2_PUBLIC_URL}/${toKey}`
+}
+
 export async function listR2Objects(prefix) {
   const objects = []
   let continuationToken