Dashboard Chat is an xterm mirror of a TUI inside the gateway, so
server-side clipboard.paste never sees the browser clipboard. Upload
pasted/dropped images to the profile's images/ dir (same place
clipboard.paste / image.attach use), then drive /image over the PTY.
Uses a dedicated /api/chat/image-upload endpoint (magic-byte check,
25MB cap, profile scope) instead of relative managed-files uploads that
400 on local dashboards without a locked root. Ctrl/Cmd+Shift+V also
tries clipboard.read() for images before falling back to text, since
preventDefault on that chord suppresses the DOM paste event.
Salvages #57912 (client composition + /image PTY drive) and folds in
#48563's upload endpoint + drop path.
Co-authored-by: bird <6666242+bird@users.noreply.github.com>
Co-authored-by: tt-a1i <53142663+tt-a1i@users.noreply.github.com>
