fix(Chunk4): purge all Pi-hole references from split files

- 08-deployment-phases: Pi-hole → AdGuard Home in Phase 1 order
- 09-open-questions: blocker replaced, decision marked resolved
- 10-appendix: removed from DockerHub table, count 16→15, dir pihole/→adguard/
- 05-network-architecture: port allocation DNS label updated
- All mirrored to master PRD

10-appendix.md

@@ -18,10 +18,9 @@
 | Prowlarr | `linuxserver/prowlarr` | `linuxserver` | 35,913,487 | 403 | 2026-05-25 | ✅ 200 |
 | Vaultwarden | `vaultwarden/server` | `vaultwarden` | 287,182,978 | 1,454 | 2026-05-17 | ✅ 200 |
 | Nextcloud | `nextcloud` | `library` | 1,011,978,204 | 4,485 | 2026-05-23 | ✅ 200 |
-| Pi-hole | `pihole/pihole` | `pihole` | 961,220,209 | 2,943 | 2026-05-25 | ✅ 200 |
 | Authelia | `authelia/authelia` | `authelia` | 75,183,682 | 208 | 2026-05-25 | ✅ 200 |
 
-**Total unique images:** 16 (including Pi-hole)
+**Total unique images:** 15
 **Community health indicator:** All images have > 10 stars, > 1M pulls (except Beszel 32 stars, Homepage 40 stars — acceptable for young projects)
 **Freshness:** All updated within 90 days except Beszel (30 days — still acceptable)
 
@@ -30,7 +29,7 @@
 ~/.ansible-repo/new-build/
 ├── phase-1/                    # Infrastructure
 │   ├── technitium/
-│   ├── pihole/
+│   ├── adguard/
 │   ├── traefik/
 │   ├── authelia/
 │   ├── portainer/