docs: Add Pi-hole Traefik config and router setup

- Added Pi-hole section to CONFIGURATIONS.md
- Includes Traefik config, DNS setup, and Asus router instructions

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

docs/CHANGELOG.md

@@ -10,6 +10,7 @@
   - IP: 10.4.2.129
   - Domain: pihole.kavcorp.com
   - Unbound configured for recursive DNS resolution
+  - Traefik config: `/etc/traefik/conf.d/pihole.yaml`
   - Deployed via ProxmoxVE community helper script
   - Tagged: adblock, dns