iso: fix packages.x86_64 (no inline comments; gstreamer-vaapi -> gst-plugin-va)

Inline comments after a package name broke kitty/flatpak (became invalid
names with trailing whitespace). gstreamer-vaapi was removed from Arch.
calamares is AUR-only -> commented pending a [tanin] rebuild decision.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

iso/build-profile/airootfs/etc/pacman.d/hooks/uncomment-mirrors.hook

@@ -0,0 +1,13 @@
+# remove from airootfs!
+[Trigger]
+Operation = Install
+Operation = Upgrade
+Type = Package
+Target = pacman-mirrorlist
+
+[Action]
+Description = Uncommenting HTTPS mirrors in /etc/pacman.d/mirrorlist...
+When = PostTransaction
+Depends = pacman-mirrorlist
+Depends = sed
+Exec = /usr/bin/sed -E -i 's/#(Server = https:)/\1/g' /etc/pacman.d/mirrorlist