fix: include GUI apps (casks) when installing from remote config

When installing from a remote config (e.g., 'openboot install jx'), GUI apps
(casks) were being silently skipped. The code only added CLI packages to
the SelectedPkgs map but never added the Casks.

This fix adds the missing loop to include casks in both:
- internal/installer/installer.go (runCustomInstall)
- internal/installer/step_packages.go (stepPackageCustomization)

Closes #17

Author: Jerry Xie

internal/installer/installer.go

@@ -142,6 +142,9 @@ func runCustomInstall(opts *config.InstallOptions, st *config.InstallState) erro
 	for _, pkg := range st.RemoteConfig.Packages {
 		st.SelectedPkgs[pkg.Name] = true
 	}
+	for _, cask := range st.RemoteConfig.Casks {
+		st.SelectedPkgs[cask.Name] = true
+	}
 
 	if err := stepInstallPackages(opts, st); err != nil {
 		return err

internal/installer/step_packages.go

@@ -146,6 +146,11 @@ func stepPackageCustomization(opts *config.InstallOptions, st *config.InstallSta
 			st.SelectedPkgs[pkg.Name] = true
 		}
 	}
+	if st.RemoteConfig != nil && len(st.RemoteConfig.Casks) > 0 {
+		for _, cask := range st.RemoteConfig.Casks {
+			st.SelectedPkgs[cask.Name] = true
+		}
+	}
 
 	count := 0
 	for _, v := range selected {