Refactor code structure for improved readability and maintainability

platform/network.go

@@ -0,0 +1,26 @@
+package platform
+
+// NetworkInfo holds discovered local network configuration from the
+// system's default-route network adapter.
+type NetworkInfo struct {
+	DNSServers []string // Ordered DNS server IPs from the default-route adapter
+	Gateway    string   // Default gateway IP (may be empty if not discoverable)
+	Interface  string   // Adapter name holding the default route (informational)
+}
+
+// NetworkDiscoverer discovers the local network configuration.
+type NetworkDiscoverer interface {
+	Discover() (NetworkInfo, error)
+}
+
+// FakeNetworkDiscoverer returns predetermined NetworkInfo for testing.
+// It is exported so packages outside of platform can use it in tests.
+type FakeNetworkDiscoverer struct {
+	Info NetworkInfo
+	Err  error
+}
+
+// Discover implements NetworkDiscoverer. Returns the pre-configured Info and Err.
+func (f *FakeNetworkDiscoverer) Discover() (NetworkInfo, error) {
+	return f.Info, f.Err
+}