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/pacman.conf

@@ -0,0 +1,25 @@
+# Build-time pacman.conf for mkarchiso (pulls live packages incl. tanin-desktop).
+# Replaces releng's pacman.conf. [tanin] is added so the airootfs can include
+# our packages. SigLevel=Never on [tanin] keeps the BUILD simple (no keyring
+# bootstrap during mkarchiso); the LIVE/target keyring trusts the key properly
+# (see airootfs/etc/pacman.conf + customize_airootfs.sh).
+[options]
+HoldPkg     = pacman glibc
+Architecture = auto
+CheckSpace
+SigLevel    = Required DatabaseOptional
+LocalFileSigLevel = Optional
+ParallelDownloads = 5
+
+[core]
+Include = /etc/pacman.d/mirrorlist
+
+[extra]
+Include = /etc/pacman.d/mirrorlist
+
+[multilib]
+Include = /etc/pacman.d/mirrorlist
+
+[tanin]
+SigLevel = Never
+Server = https://git.openbureau.ch/api/packages/karim/arch/tanin/$arch