feat: add GitHub Pages docs site (Just the Docs), split packagechooser, disable IA upload

- docs/: new 13-page Jekyll site with Just the Docs theme
  - Home, Building, Installer, Packages, CI/CD, Development
  - Desktop Environments (with GNOME joke), Wallpapers, Launcher
  - Overlays, Root Overlay, Live Overlay
- .github/workflows/pages.yml: build & deploy docs from docs/ on
  push to master (only when docs/ changes)
- .github/workflows/build.yml: temporarily disable Internet Archive
  upload (if: false) until ISO is stable
- live-overlay/settings.conf: add instances section for init + desktop
  packagechooser instances
- live-overlay/modules/packagechooser_init.conf: init system selector
  (OpenRC, Runit, S6, Dinit) via netinstall-add method
- live-overlay/modules/packagechooser_desktop.conf: DE selector
  (Plasma, Xfce, Cinnamon, MATE, LXQt, i3, Sway, Hyprland + No Desktop)
  via legacy method
- README.md, AGENTS.md: fix sudo buildiso -> sudo ./buildiso, add note
  about system buildiso lacking --overwrite='*'
- .gitignore: add docs/_site/

docs/index.md

@@ -0,0 +1,36 @@
+---
+title: Home
+layout: home
+nav_order: 1
+---
+
+# Antergos NeXT
+
+> **Migration complete!** Antergos NeXT has migrated from systemd/Arch to OpenRC/Artix. Builds are stable, the installer works.
+
+A community revival of Antergos — built on **Artix Linux** with **OpenRC**, **KDE Plasma**, and the **Calamares** installer (offline + online modes).
+
+## Quick links
+
+- [Building the ISO](building) — set up and build locally
+- [Installer](installer) — Calamares modes, init & DE selectors
+- [Custom packages](packages) — PKGBUILDs, repo setup
+- [CI/CD](ci) — GitHub Actions pipeline
+- [Development](development) — contributing, gotchas, conventions
+
+## What changed
+
+| Area | Original Antergos | Antergos NeXT |
+|------|-------------------|---------------|
+| Base | Arch Linux (systemd) | Artix Linux (OpenRC) |
+| Desktop | GNOME | KDE Plasma |
+| Installer | Custom Cnchi | Calamares |
+| Build | archiso | artools (`buildiso`) |
+
+## Sources
+
+- [Artix Linux](https://artixlinux.org)
+- [artools](https://gitea.artixlinux.org/artix/artools)
+- [Calamares](https://codeberg.org/calamares/calamares)
+- [antergos-packages](https://github.com/Antergos-NeXT/antergos-packages)
+- [Original wallpapers](https://github.com/Antergos/wallpapers)