[client] Replace exclusion routes with scoped default + IP_BOUND_IF on macOS (#5918)

client/net/env_mobile.go

@@ -0,0 +1,25 @@
+//go:build ios || android
+
+package net
+
+// Init initializes the network environment for mobile platforms.
+func Init() {
+	// no-op on mobile: routing scope is owned by the VPN extension.
+}
+
+// AdvancedRouting reports whether routing loops can be avoided without using exclusion routes.
+// Always returns true on mobile since routes cannot be handled dynamically and the VPN extension
+// owns the routing scope.
+func AdvancedRouting() bool {
+	return true
+}
+
+// SetVPNInterfaceName is a no-op on mobile.
+func SetVPNInterfaceName(string) {
+	// no-op on mobile: the VPN extension manages the interface.
+}
+
+// GetVPNInterfaceName returns an empty string on mobile.
+func GetVPNInterfaceName() string {
+	return ""
+}