fix: packages.conf format, add init icons, instant wallpaper

- packages.conf: fix operations format (strings -> empty list)
- netinstall.yaml: remove empty Style group
- packagechooser.conf: add Breeze-style init system SVG icons
- wallpaper: pre-bake config in skel for instant wallpaper, remove wait loop
- AGENTS.md: add GPG signing instructions

iso-profiles/antergos/live-overlay/etc/calamares/modules/packagechooser.conf

@@ -13,7 +13,7 @@ items:
     - id: OpenRC
       name: openrc
       description: "OpenRC init system"
-      screenshot: ""
+      screenshot: "/etc/calamares/modules/images/openrc.svg"
       netinstall:
         name: "openrc"
         description: "OpenRC init system"
@@ -84,7 +84,7 @@ items:
     - id: Dinit
       name: dinit
       description: "Dinit init system"
-      screenshot: ""
+      screenshot: "/etc/calamares/modules/images/dinit.svg"
       netinstall:
         name: "dinit"
         description: "Dinit init system"
@@ -154,7 +154,7 @@ items:
     - id: S6
       name: s6
       description: "S6 init system"
-      screenshot: ""
+      screenshot: "/etc/calamares/modules/images/s6.svg"
       netinstall:
         name: "s6"
         description: "S6 init system"
@@ -225,7 +225,7 @@ items:
     - id: Runit
       name: runit
       description: "Runit init system"
-      screenshot: ""
+      screenshot: "/etc/calamares/modules/images/runit.svg"
       netinstall:
         name: "runit"
         description: "Runit init system"