release: v4.8.10 user-configurable STUN/TURN servers

- add header gear + connection-screen entry points to Advanced network settings
- render the ICE settings modal at the app root (reachable from any screen via event)
- remove the standalone relay-only toggle/description from the start screen
  (relay-only now lives in the advanced settings panel)
- fix crash from referencing main-component state inside EnhancedConnectionSetup
- bump version to 4.8.10 across header, manifest, README, init message, disclaimer
- document the feature in CHANGELOG and README

src/components/ui/Header.jsx

@@ -539,7 +539,7 @@ const EnhancedMinimalHeader = ({
                         React.createElement('p', {
                             key: 'subtitle',
                             className: 'text-xs sm:text-sm text-muted hidden sm:block'
-                        }, 'End-to-end freedom v4.8.9')
+                        }, 'End-to-end freedom v4.8.10')
                     ])
                 ]),
 
@@ -549,6 +549,17 @@ const EnhancedMinimalHeader = ({
                     className: 'flex items-center space-x-2 sm:space-x-3'
                 }, [
 
+                    React.createElement('button', {
+                        key: 'network-settings',
+                        type: 'button',
+                        onClick: () => window.dispatchEvent(new CustomEvent('securebit:open-network-settings')),
+                        title: 'Advanced network settings (STUN/TURN)',
+                        'aria-label': 'Advanced network settings',
+                        className: 'w-8 h-8 rounded-full flex items-center justify-center text-muted hover:text-primary hover:bg-white/5 transition-colors duration-200'
+                    }, [
+                        React.createElement('i', { key: 'i', className: 'fas fa-network-wired text-sm' })
+                    ]),
+
                     displaySecurityLevel && React.createElement('div', {
                         key: 'security-level',
                         className: 'hidden md:flex items-center space-x-2 cursor-pointer hover:opacity-80 transition-opacity duration-200',