fix: enable browser executable selection

internal/platform/files/executable_picker_other.go

@@ -0,0 +1,16 @@
+//go:build !windows
+
+package files
+
+import (
+	"context"
+	"errors"
+)
+
+type unsupportedExecutablePicker struct{}
+
+func NewExecutablePicker() ExecutablePicker { return unsupportedExecutablePicker{} }
+
+func (unsupportedExecutablePicker) ChooseExecutable(context.Context) (string, error) {
+	return "", errors.New("executable picker is only supported on Windows")
+}