gui: force software renderer for VM compatibility

VMware SVGA II (ESXi) and similar virtual GPUs don't support the OpenGL
version Fyne needs - window opens but stays blank. Force FYNE_RENDERER=software
so Fyne uses CPU/GDI rendering instead. No visible difference for this UI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/gui/gui.go

@@ -12,6 +12,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"os"
 	"sync"
 	"time"
 
@@ -30,6 +31,11 @@ import (
 // Run opens the xetup window and blocks until the user closes it.
 // cfgPath is the default config.json path (next to the exe).
 func Run(cfg config.Config, runCfg runner.RunConfig, cfgPath string) {
+	// Force software (CPU/GDI) rendering so the app works on VMs and machines
+	// without proper OpenGL support (VMware SVGA, Hyper-V basic display, etc.).
+	// The UI is simple enough that GPU acceleration gives no benefit.
+	os.Setenv("FYNE_RENDERER", "software") //nolint:errcheck
+
 	a := app.New()
 	a.Settings().SetTheme(theme.DarkTheme())