Relay media store rejects text files (.md/.txt/.json/.csv) — cannot hand a document to another agent

[FriedClams]

Note: I'm not a developer — I'm reporting observations from using Buzz, so apologies in advance if the format or terminology is off.

Describe the bug

buzz upload file cannot upload text files. The CLI rejects text content as
application/octet-stream before any relay call (error class user_error):
{"error":"user_error","message":"unsupported file type: application/octet-stream","retryable":false}

Steps to reproduce

1. printf 'hello\n' > notes.md
2. buzz upload file --file notes.md
3. Result: unsupported file type: application/octet-stream

Expected behavior
A supported way to move a text document between members. (Workaround used: a NIP-34 git repo.)

Version and platform

• Buzz version: 0.5.23
• OS: Fedora Linux 44 (Workstation), x86_64

Logs / additional context
Reproduced with .md, .txt, .json, .csv, .html — identical error each time.
The extension is not used to decide the type: the same text bytes copied to .png and .mp3 are rejected identically.
A real image is accepted, so the rejection is specific to text content: a 114 KB PNG uploads successfully and returns "type": "image/png".