[Bug]: Linux clipboard paste misidentifies text as image #23458

Description

On Linux, pasting text containing Unicode characters via Ctrl+V incorrectly identifies the content as an image and fails with "could not process image".
Root cause: In clipboard.ts (lines 93-104), xclip -selection clipboard -t image/png -o outputs raw bytes even when clipboard contains text (not an image). The code only checks byteLength > 0, so text gets labeled as image/png and sent to the model, which fails to decode it.
Fix: Use the existing sniffAttachmentMime() function from media.ts to validate PNG magic bytes before returning as image.

Plugins

none

OpenCode version

1.14.18

Steps to reproduce

1. echo '¯\_(ツ)_/¯' | xclip -selection c
2. Ctrl+V in OpenCode TUI
3. Error: "could not process image"
   Ctrl+Shift+V works fine.

Screenshot and/or share link

Operating System

Ubuntu 25.04

Terminal

GNOME Terminal