chore: migrate from calamares to anaconda installer

Remove Calamares compilation and configuration, replace with Anaconda installer setup.

Changes:
- Remove Calamares-related entries from .gitignore
- Update README with migration status from Calamares to Anaconda
- Rename setup-calamares.sh references to setup-aur.sh
- Remove Calamares packages from package lists
- Add anaconda and liveimg payload packages
- Add Anaconda kickstart configuration (interactive-defaults.ks)
- Update boot sequence documentation: remove Calamares desktop selection, simplify to Openbox live environment
- Remove Calamares-specific troubleshooting entries
- Clean up .xinitrc and .zlogin to remove Calamares launcher
- Update build scripts to reference local repo generically instead of Calamares-specific

.gitignore

@@ -2,15 +2,3 @@ out/
 local-repo/
 configs/baseline/airootfs/etc/systemd/system/multi-user.target.wants/
 configs/releng/airootfs/etc/systemd/system/multi-user.target.wants/
-# Ignore le contenu généré de usr/lib (libs Calamares) MAIS conserve le module
-# de choix de bureau FWS — sinon il est absent des clones et la sélection
-# multi-desktop est cassée pour quiconque clone le dépôt.
-configs/baseline/airootfs/usr/lib/*
-!configs/baseline/airootfs/usr/lib/calamares/
-configs/baseline/airootfs/usr/lib/calamares/*
-!configs/baseline/airootfs/usr/lib/calamares/modules/
-configs/baseline/airootfs/usr/lib/calamares/modules/*
-!configs/baseline/airootfs/usr/lib/calamares/modules/fws-desktop-choice/
-configs/baseline/airootfs/usr/bin/
-configs/baseline/airootfs/usr/include/
-configs/baseline/airootfs/usr/share/calamares/branding/default/