docs(wiki): add IX hosting server system article + radio site infra

- New wiki/systems/ix-server.md: IX web host (172.16.3.10) facts, the
  ACG hosted sites table, and a full record of radio.azcomputerguru.com
  (Astro static + React 19 islands; source in projects/radio-show/website/;
  build npm run build -> dist -> rsync to cPanel doc root).
- index.md: list the new IX systems article.
- radio-show.md: fix the stale "ix-server.md may not exist" backlink.
- memory reference_radio_website.md: add stack detail (React islands,
  wavesurfer/fuse, node>=22) + pointer to the new wiki article.

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

wiki/index.md

@@ -70,6 +70,7 @@ Run `/wiki-lint` to check for stale entries and broken backlinks.
 | [Jupiter](systems/jupiter.md) | 172.16.3.20 — Unraid primary NAS; virsh host for all VMs; Docker: NPM, Gitea, Seafile; iDRAC at 172.16.1.73 | 2026-05-24 |
 | [Pluto (Claude-Builder)](systems/pluto.md) | 172.16.3.36 — Windows Server 2019 virsh VM on Jupiter; exclusive Windows MSI + cargo build server for GuruRMM | 2026-05-24 |
 | [Uranus](systems/uranus.md) | 172.16.3.21 — Unraid secondary (Dell R730xd); OwnCloud archive storage only; formerly Saturn's IP (reused Apr 2026); RAM too low for VMs | 2026-05-24 |
+| [IX Web Hosting Server](systems/ix-server.md) | 172.16.3.10 / 72.194.62.5 — cPanel/WHM (CloudLinux 9.7); hosts ACG static sites incl. **radio.azcomputerguru.com** (Astro, source in `projects/radio-show/website/`), public site, Flarum community, Matomo analytics + ~87 client WordPress; behind Cloudflare tunnel `acg-origin` | 2026-06-05 |
 
 ## Patterns