docs: rework all pages to Artix Wiki quality

- index.md: add download link + stable release announcement
- building.md: add troubleshooting section (cache, squashfs, compression)
- ci.md: IA upload enabled, push trigger removed (manual dispatch only)
- development.md: add all gotchas from AGENTS.md (SDDM theme ordering,
  pipewire launcher, antergos-release in basestrap, CI changes)
- installer.md: document fixed issues (audio, SDDM, os-release)
- packages.md: add pipewire fork, antergos-sddm-theme, antergos-release
- launcher.md: expand with module configs
- init-systems.md: Chimera uses dinit, OpenRC marked as broken
- openrc.md: add broken warning banner
- wallpapers.md: default is antergos-wallpaper.png (not Adwaita Morning)
- overlays: clean up explanations and symlink behavior
- desktop-environments.md: add Discover note, clean up GNOME entry
- dinit.md, runit.md, s6.md: polish and add troubleshooting sections

docs/overlay-root.md

@@ -14,38 +14,35 @@ Files in `iso-profiles/antergos/root-overlay/` are merged into the root squashfs
 ```
 root-overlay/
 ├── etc/
-│   ├── os-release            # Antergos NeXT branding
-│   ├── pacman.conf           # Includes [antergos-pkgs] repo
+│   ├── pacman.conf               # Includes [antergos-pkgs] repo
 │   ├── sddm.conf.d/
-│   │   └── kde_settings.conf # SDDM theme + Wayland session
+│   │   └── kde_settings.conf     # SDDM theme + Wayland session
 │   └── skel/
 │       └── .config/
 │           └── autostart/
 │               └── antergos-wallpaper.desktop  # One-shot wallpaper setter
-└── usr/
-    └── local/
-        └── bin/
-            └── set-antergos-wallpaper.sh  # Wallpaper script
+├── usr/
+│   └── local/
+│       └── bin/
+│           └── set-antergos-wallpaper.sh       # Wallpaper script
 ```
 
 ## Key files
 
-### `etc/os-release`
-
-Identifies the system as "Antergos NeXT" to tools, installers, and the login manager.
-
 ### `etc/pacman.conf`
 
-Adds the `[antergos-pkgs]` custom repo so installed systems can receive updates.
+Adds the `[antergos-pkgs]` custom repo so installed systems can receive updates from our package repository. The `SigLevel = Optional TrustAll` is needed because our packages are not signed with official Artix keys.
 
 ### `etc/sddm.conf.d/kde_settings.conf`
 
-Sets the SDDM session to `plasma.desktop` (Wayland) by default.
+Sets the SDDM session to `plasma.desktop` (Wayland) by default. Also controls the SDDM theme — see the note below.
+
+> **Note:** The SDDM theme is set to `Current=antergos` in this file. However, KDE's SDDM KCM may overwrite this file on first login to `Current=breeze`. To ensure the Antergos theme persists, the `antergos-sddm-theme` package ships a `theme.conf` that sorts after `kde_settings.conf` alphabetically, so its `Current=antergos` always wins.
 
 ### `etc/skel/.config/autostart/antergos-wallpaper.desktop`
 
-Runs the wallpaper setter on first login. Uses `X-KDE-autostart-phase=2` to run after Plasma has initialized.
+Runs the wallpaper setter on first login. Uses `X-KDE-autostart-phase=2` to run after Plasma has initialized. This is necessary because Plasma overwrites the wallpaper config from `/etc/skel/` on first login.
 
 ### `usr/local/bin/set-antergos-wallpaper.sh`
 
-Applies the wallpaper via `plasma-apply-wallpaperimage` and creates `~/.config/antergos-wallpaper-set` marker to prevent re-running.
+Applies the wallpaper via `plasma-apply-wallpaperimage` and creates `~/.config/antergos-wallpaper-set` marker to prevent re-running on subsequent logins.