add: Pi-hole LXC with Unbound recursive DNS

- IP: 10.4.2.129 on pm2
- Domain: pihole.kavcorp.com
- Unbound configured for recursive DNS resolution

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/INFRASTRUCTURE.md

@@ -43,6 +43,7 @@
 | **Vaultwarden** | 10.4.2.212 | LXC 125 (pm4) | vtw.kavcorp.com | Built-in |
 | **Immich** | 10.4.2.24:2283 | LXC 126 (pm4) | immich.kavcorp.com | Built-in |
 | **Gitea** | 10.4.2.7:3000 | LXC 127 (pm4) | git.kavcorp.com | Built-in |
+| **Pi-hole** | 10.4.2.129 | LXC (pm2) | pihole.kavcorp.com | Built-in |
 | **KavNas** | 10.4.2.13 | Synology NAS | - | NAS auth |
 
 ## Storage Architecture