feat(inbox): wire mail attachments through CrmInboxAdapter

uploadAttachment presigns via crm.media.presignUpload + PUTs bytes to IIOS
storage; mailReply/composeInternal/composeExternal forward attachment refs
to crm.mail.reply/internal/send (server already supported them).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package-lock.json

@@ -1030,7 +1030,7 @@
     "node_modules/@insignia/iios-messaging-ui": {
       "version": "0.1.0",
       "resolved": "file:../iios/packages/iios-messaging-ui/insignia-iios-messaging-ui-0.1.0.tgz",
-      "integrity": "sha512-RoXEI/SgzYM2Zj+XvwNkc3rrDQ5kDa/oqsCo2wkZxwRs3bVHJuRoQR+c713wgaWK+MmqIg0cetXQ//rfJvpBbg==",
+      "integrity": "sha512-qJc7+34VwPcsuaucXcUe7LbW7CAvVcGBUnUR6ktuHHISpGVWzXEni9rjUiBI+Baw3UxvUFbtmIuqT1DTXIeegw==",
       "peerDependencies": {
         "@insignia/iios-kernel-client": "*",
         "react": ">=18"