feat(cmd): add installall/uninstallall; fix startall/stopall and service lifecycle

- startall now uses systemctl start (not enable --now)
- stopall now uses systemctl stop (not disable --now)
- add installall command (bulk install with --dry-run support)
- add uninstallall command (bulk disable+remove in reverse order)
- fix docker ExecStart to use -a flag so the process stays attached
- prefix ExecStop with - so a stop-on-already-dead container does not fail the unit

cmd/uninstallall.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/spf13/cobra"
+	"github.com/warkanum/unitdore/config"
+	"github.com/warkanum/unitdore/systemd"
+)
+
+var uninstallallCmd = &cobra.Command{
+	Use:   "uninstallall",
+	Short: "Stop, disable, and remove service files for all installed units",
+	Long:  `Uninstallall runs 'systemctl disable --now' and removes the .service file for every installed unit, in reverse startup order.`,
+	RunE:  runUninstallall,
+}
+
+func init() {
+	rootCmd.AddCommand(uninstallallCmd)
+}
+
+func runUninstallall(cmd *cobra.Command, args []string) error {
+	cfg, err := config.Load(configPath)
+	if err != nil {
+		return err
+	}
+
+	prefix, suffix := cfg.Prefix, cfg.Suffix
+
+	units := make([]config.Unit, len(cfg.Units))
+	copy(units, cfg.Units)
+	sort.Slice(units, func(i, j int) bool {
+		if units[i].Order != units[j].Order {
+			return units[i].Order > units[j].Order
+		}
+		return units[i].Name > units[j].Name
+	})
+
+	removed := 0
+	failed := 0
+
+	for _, u := range units {
+		if !systemd.IsInstalled(u, prefix, suffix) {
+			continue
+		}
+		svcName := systemd.ServiceName(u, prefix, suffix)
+		fmt.Printf("  ■ disabling %s...\n", svcName)
+		if err := systemd.Disable(u, prefix, suffix); err != nil {
+			fmt.Printf("  ✗ failed to disable %s: %v\n", u.Name, err)
+			failed++
+			continue
+		}
+		path, _ := systemd.UnitPath(u, prefix, suffix)
+		fmt.Printf("  ✗ removing %s...\n", path)
+		if err := systemd.Uninstall(u, prefix, suffix); err != nil {
+			fmt.Printf("  ✗ failed to remove %s: %v\n", u.Name, err)
+			failed++
+			continue
+		}
+		fmt.Printf("  ✓ uninstalled: %s\n", u.Name)
+		removed++
+	}
+
+	fmt.Printf("\nDone. Uninstalled: %d  Failed: %d\n", removed, failed)
+	return nil
+}