The generated-link "Copy link:" row stayed visible after creating,
looking like the form hadn't reset — but the new link was already in
the Active links list with its own Copy button. Drop the redundant
preview row; on create, reset the form and briefly highlight the new
entry in the active list. Removes the now-dead shareNewLinkRow markup
and copyShareLink().
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>