feat(cmd): register all Plan 3a modules in install command

Replace the init()-time hello toy-module registration with a
buildRegistry(cfg) helper called from the install RunE that wires the
ten Plan 3a modules (packages, gittools, starship, yazi, zsh, fonts,
zellij, themes, arduinocli, shellconfig) against a shared ExecRunner,
Pacman, Yay, and GitClient.

cmd/archduino/main.go

@@ -13,7 +13,16 @@ import (
 	"github.com/MDietermann/ArduinoArchSetup/internal/config"
 	"github.com/MDietermann/ArduinoArchSetup/internal/engine"
 	"github.com/MDietermann/ArduinoArchSetup/internal/module"
-	"github.com/MDietermann/ArduinoArchSetup/internal/modules/hello"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/arduinocli"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/fonts"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/gittools"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/packages"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/shellconfig"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/starship"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/themes"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/yazi"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/zellij"
+	"github.com/MDietermann/ArduinoArchSetup/internal/modules/zsh"
 	"github.com/MDietermann/ArduinoArchSetup/internal/platform"
 	"github.com/MDietermann/ArduinoArchSetup/internal/privilege"
 	"github.com/MDietermann/ArduinoArchSetup/internal/state"
@@ -24,14 +33,35 @@ import (
 
 var version = "dev"
 
-// Registry is the global module registry. Tasks in Plan 3 will register
+// buildRegistry constructs a module registry populated with all Plan 3a
-// real modules into it via init(). Task 12 registers the hello toy module.
+// modules, wired against the provided config and platform dependencies.
-var Registry = module.NewRegistry()
+// It replaces the earlier init()-time hello-module registration now that
+// the real modules need runtime config to be instantiated.
+func buildRegistry(cfg config.Config) (*module.Registry, error) {
+	reg := module.NewRegistry()
+	runner := platform.ExecRunner{}
+	pm := platform.NewPacman(runner)
+	yay := platform.NewYay(runner)
+	git := platform.GitClient{Runner: runner}
 
-func init() {
+	mods := []module.Module{
-	if err := Registry.Register(hello.Module{}); err != nil {
+		packages.New(cfg.Packages.Base, pm),
-		panic(err)
+		gittools.New([]string{"lazygit"}, pm),
+		starship.New([]string{"starship"}, pm),
+		yazi.New([]string{"yazi"}, pm),
+		zsh.New(cfg.Zsh, pm, git),
+		fonts.New(cfg.Fonts, pm, yay),
+		zellij.New(cfg.Zellij, pm),
+		themes.New(cfg.Themes),
+		arduinocli.New(cfg.ArduinoCLI, runner),
+		shellconfig.New(cfg.ShellConfig),
 	}
+	for _, m := range mods {
+		if err := reg.Register(m); err != nil {
+			return nil, err
+		}
+	}
+	return reg, nil
 }
 
 func main() {
@@ -92,7 +122,12 @@ func newInstallCmd() *cobra.Command {
 				return err
 			}
 
-			selected, err := resolveSelection(Registry, cfg, only, skip)
+			reg, err := buildRegistry(cfg)
+			if err != nil {
+				return fmt.Errorf("build registry: %w", err)
+			}
+
+			selected, err := resolveSelection(reg, cfg, only, skip)
 			if err != nil {
 				return err
 			}
@@ -117,7 +152,7 @@ func newInstallCmd() *cobra.Command {
 				// always uses plain output because the dashboard has nothing
 				// to animate when no Apply happens.
 				reporter := engine.NewPlainReporter(os.Stdout)
-				sum, runErr = engine.Run(ctx, Registry, engine.RunOptions{
+				sum, runErr = engine.Run(ctx, reg, engine.RunOptions{
 					Selected:    selected,
 					DryRun:      dryRun,
 					HaltOnError: halt,
@@ -126,7 +161,7 @@ func newInstallCmd() *cobra.Command {
 			} else {
 				// TUI path: wizard → dashboard. If the user does not confirm,
 				// we exit cleanly with a zero-summary and no error.
-				initial := tui.NewWizardState(cfg, Registry)
+				initial := tui.NewWizardState(cfg, reg)
 				// Pre-filter the wizard's module list by --only/--skip so the
 				// user cannot accidentally widen selection in the TUI beyond
 				// what they asked for on the CLI.
@@ -140,7 +175,7 @@ func newInstallCmd() *cobra.Command {
 					}
 				}
 
-				finalState, confirmed, werr := wizard.Run(ctx, Registry, initial)
+				finalState, confirmed, werr := wizard.Run(ctx, reg, initial)
 				if werr != nil {
 					return werr
 				}
@@ -149,7 +184,7 @@ func newInstallCmd() *cobra.Command {
 					return nil
 				}
 				// Either the CLI flag or the wizard toggle can force halt-on-error.
-				sum, runErr = dashboard.Run(ctx, Registry, finalState, halt || finalState.HaltOnError)
+				sum, runErr = dashboard.Run(ctx, reg, finalState, halt || finalState.HaltOnError)
 			}
 
 			ended := time.Now().UTC()