style(settings): fold the Happ settings into four tabs

Seven tabs, several holding one or two settings, made the page hard to
scan. The encrypted-links switch moves above the tabs under
auto-detection, the colour profile joins the banners under Appearance &
Theme, and Android per-app proxy joins Network & TUN Engine. The QR
modal's settings link no longer needs a happTab selector, and the three
orphaned tab-label keys are dropped from every locale.

frontend/src/pages/settings/SubscriptionGeneralTab.tsx

@@ -414,8 +414,6 @@ export default function SubscriptionGeneralTab({
               updateSetting={updateSetting}
               isMobile={isMobile}
               remoteSourceBadge={remoteSourceBadge}
-              // QR settings links select the link control; ordinary Happ visits still start on routing.
-              defaultActiveTab={searchParams.get('happTab') === 'links' ? 'links' : 'routing'}
             />
           ),
         },