Images and GitHub issues/PRs now live in one draft-store list (ComposerAttachment union) with cwd persisted on the draft. Paperclip becomes a + drop-up menu; queue button removed. Each pill uses a shared AttachmentPill wrapper with a corner-X that mirrors the auto-update toast spec. Pill body opens the attachment: GitHub via openExternalUrl, images via a new fullscreen AttachmentLightbox. GitHub picker auto-closes on select.
The Create button on the new workspace screen was visible but clicking
it did nothing — submitAgentInput() still rejected empty payloads as
"noop". Thread allowEmptySubmit through Composer into submitAgentInput
so the callback fires and workspace creation + redirect completes.
Adds regression test for the empty-submit path.