The per-annotation delete button (a 44px circular control pinned to the
box's top-right) overlapped the box below and obscured the underlying
document text. It was redundant: every user-drawn annotation has a
transcription block, and the right-hand panel already offers a
non-overlapping delete per block that cascades to the annotation.
Remove the visible button and its `deleteVisible` derived. Keep the
keyboard Delete shortcut (and its `showDelete`/`onDeleteRequest`/
`deleteAnnotation` wiring) — it obscures nothing and remains a
power-user path and the only cleanup route for orphan annotations.
Tests: replace the button-render/click specs with contract tests
asserting no delete button ever renders; repoint the e2e delete flow
to the keyboard shortcut + confirm dialog.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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