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/calamares/modules/shellprocess-flathub.conf

@@ -0,0 +1,5 @@
+---
+dontChroot: false
+timeout: 30
+script:
+- "flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo"