* desktop: don't copy non-message items when selecting message text
Selecting text across messages also copied the text of event/info
items (e.g. "connected") that fell inside the selection, even though
those items are never highlighted as selected.
getSelectedCopiedText emitted text for every merged item between the
selection bounds. Event/info items have no msgContent but a non-empty
text, so as interior items their text was copied. Skip items whose
content has no msgContent - only real messages are copyable.
* plans: add 2026-05-20-fix-copy-non-msg-items.md