Adds a "⧉ copy" button next to the pickup id that copies the id to the
clipboard (flips to "✓ copied"). The Booth serves over plain HTTP on a LAN IP,
where navigator.clipboard is undefined (secure-context only) — so the handler
falls back to a hidden-textarea execCommand('copy') that works over HTTP.
Verified on the LAN-IP (non-secure) path: isSecureContext=false, clipboard API
absent, button state flips, no errors. Reusable via any .copy-btn[data-copy].
vh
d813f152ce