feat(dhcp): DHCPv4-Server via Kea (kea-dhcp4-server) — v1.2.92

Verwalteter DHCPv4-Server analog Unbound/Squid/Chrony.
- Migration 0041: dhcp_settings (singleton, node-lokal), dhcp_subnets, dhcp_reservations.
- internal/kea: Renderer baut Kea-JSON via Go-Struct→Marshal (garantiert valide), managed /etc/edgeguard/kea/kea-dhcp4.conf (Symlink von /etc/kea), Service-Lifecycle an enabled gekoppelt (default AUS, kein rogue DHCP). Interface per NAME (cluster-sicher, kein node-lokaler FK).
- internal/services/dhcp + internal/handlers/dhcp.go: Settings + Subnet/Reservation-CRUD, Validierung (CIDR/IP/MAC/interface exists).
- configgen: Stop/Enable/DisableService. Firewall: AutoFWRule.Iface → udp/67 pro LAN-Interface gescopt (kein WAN). Cluster: subnets/reservations repliziert (hashSpec), dhcp_settings node-lokal (localOnlyTables).
- main.go + render.go + WithAllReloaders Wiring. Packaging: kea-dhcp4-server Dependency, /etc/edgeguard/kea Dir, Symlink, disable-on-install, sudoers (restart/stop/enable/disable).
- UI: DHCP-Seite (Settings + Subnets + Reservierungen pro Subnet), Route/Nav/i18n de/en, HA-Warnung 'nur auf einer Node aktivieren'.
- Tests (guarded EG_FWTEST_DSN): Kea-Renderer gegen DB (valides JSON + Felder), FW-Auto-Rule-Iface inkl. nft -c. Scope v1: DHCPv4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/configgen/configgen.go

@@ -99,6 +99,33 @@ func RestartService(name string) error {
 	return nil
 }
 
+// StopService runs `sudo -n systemctl stop <name>.service`.
+func StopService(name string) error {
+	cmd := exec.Command("sudo", "-n", "/usr/bin/systemctl", "stop", name+".service")
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("sudo systemctl stop %s.service: %w (output: %s)", name, err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+// EnableService runs `sudo -n systemctl enable <name>.service` (boot-persistent).
+func EnableService(name string) error {
+	cmd := exec.Command("sudo", "-n", "/usr/bin/systemctl", "enable", name+".service")
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("sudo systemctl enable %s.service: %w (output: %s)", name, err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+// DisableService runs `sudo -n systemctl disable <name>.service`.
+func DisableService(name string) error {
+	cmd := exec.Command("sudo", "-n", "/usr/bin/systemctl", "disable", name+".service")
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("sudo systemctl disable %s.service: %w (output: %s)", name, err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
 // EtcEdgeguard is the on-target config root. Templated path used by
 // all renderers — never let renderers hard-code their own.
 const EtcEdgeguard = "/etc/edgeguard"