feat: implement dynamic server list loading from API

Add internal/api package to fetch server list from /api/servers.json endpoint

Replace hardcoded server list with dynamic API call

Implement loading states, error handling, and refresh capability

internal/ui/ui_test.go

@@ -0,0 +1,9 @@
+// package ui contains the Fyne GUI bootstrap and wiring.
+package ui
+
+import "testing"
+
+// Dummy test to ensure package compiles
+func TestUIPackage_Compiles(t *testing.T) {
+	// This test ensures the ui package compiles without errors
+}