Long-press (touch) / right-click (desktop) on a finalized message now
opens a context menu anchored to the bubble: Copy / Select messages /
Delete. The multi-select toolbar gains a Copy button that joins the
selected messages in display order. Copies raw markdown so formatting
survives pasting into other markdown apps; blank text is a no-op.
Cancelling a menu-opened delete confirm clears the staged selection so
the bubble doesn't stay highlighted.
ARIA