Browsers report an empty file.type for files with no OS-registered MIME (esp.
.md), which then went up as application/octet-stream and got rejected. Infer
the type from the extension for the text types IIOS allows (md/markdown/html/
htm/txt/csv) so those attachments upload.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
- media-api: useUploadAttachment (presign → direct PUT to IIOS storage),
useDownloadUrl (short-lived signed URL), isImage, 25MB cap
- socket + REST send now carry attachment {contentRef, mimeType, sizeBytes}
- composer: 📎 attach button, staged chip, send with attachment (text optional)
- MessageBubble renders AttachmentView (inline image or file chip), aligned
to the message side; empty bubble suppressed for attachment-only messages
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
maaz519