Rename the SPA globals injected by Go to drop the ad-hoc dunder shape
and free up the bare `webBasePath` name (still the DB setting key)
from colliding with the JS global it used to share:
window.__X_UI_BASE_PATH__ -> window.X_UI_BASE_PATH
window.__X_UI_CUR_VER__ -> window.X_UI_CUR_VER
Also rework the QR-Code modal to fold every QR (subscription + JSON
sub URL, share links, WireGuard config/peer links) into a single
a-collapse with one panel per QR. Subscription panels are listed
first and open by default; everything else stays collapsed so a
multi-link inbound no longer scrolls forever.