feat: HA-Cluster v1.2.x — Split-Brain, TOTP, Enterprise-FW, Drift-Fix, VIP-Recovery

- keepalived: pg_role='standby' hat Vorrang vor role für BACKUP-Bestimmung
- keepalived-master.sh: gecrasht Dienste beim MASTER-Übergang starten (nicht nur reload)
- confighash: ip_addresses per Interface-Name hashen statt per FK (Cross-Node-Drift-Fix)
- TOTP/2FA: RFC 6238 — Setup-Flow, QR-Code, Admin-Disable; two-step Login
- Firewall-UI: Enterprise-Design — auto-Beschreibung, icon-only Actions, zero-hit Indikator
- fe80-Filter: Link-local IPv6 aus NTP/DNS Listen-Dropdowns entfernen
- VIP-Dashboard, Dual-Path VRRP, GW-Tracking (Migrations 0033/0034)
- Forward Proxy + DNS erweiterte Einstellungen (Migrations 0031/0032)
- unbound-control: edgeguard in unbound-Gruppe via postinst

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/unbound/unbound.cfg.tpl

@@ -31,8 +31,10 @@ server:
     do-tcp: yes
     cache-min-ttl: {{.Settings.CacheMinTTL}}
     cache-max-ttl: {{.Settings.CacheMaxTTL}}
-    msg-cache-size: 64m
-    rrset-cache-size: 128m
+    msg-cache-size: {{.Settings.MsgCacheSizeMB}}m
+    rrset-cache-size: {{.Settings.RRSetCacheSizeMB}}m
+    prefetch: {{if .Settings.Prefetch}}yes{{else}}no{{end}}
+    serve-expired: {{if .Settings.ServeExpired}}yes{{else}}no{{end}}
     num-threads: 2
 
     # Hardening