- Migration 073: attachment_url column in chat_messages
- upload.ts: add 'chat' folder to ALLOWED_FOLDERS
- chat.ts: accept attachment_url in send message, return it in GET messages
- api.ts: attachmentUrl in ChatMessage type, uploadImage() with raw FormData fetch
- ChatWidget: paperclip button, file preview thumbnail with remove, image display
inline in message bubbles (clickable, opens original), send enabled with image only
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
