Merge pull request 'Always-packages: install the multimedia dnf group' (#17) from feat/always-multimedia-group into main

Adds '@multimedia' as an ALWAYS_PACKAGES entry and teaches the always-loop
to route '@group' lines through install_group, so a group is checked for
existence first and a bad name prints the system's real group list instead
of dnf's 'No match for argument: @multimedia'.

Group install failures warn in red and continue, like every other
always-package line.

setup.sh

@@ -395,6 +395,9 @@ fi
 #------------------------------------------
 # Add a category here and it is installed on every run, no questions asked.
 # Keep each category one line so diffs stay readable.
+# A line that is a dnf comps GROUP is written "@group" (e.g. "@multimedia");
+# the loop below routes it through install_group, which reports a bad group
+# name with the list of groups this system actually has.
 ALWAYS_PACKAGES=(
     # Terminals
     "ghostty ghostty-bash-completion zsh zsh-syntax-highlighting"
@@ -414,6 +417,10 @@ ALWAYS_PACKAGES=(
     "libreoffice"
     # Multimedia
     "mpv gstreamer1-plugin-openh264 mozilla-openh264"
+    # Multimedia codecs: dnf comps group 'multimedia' (the group Fedora's own
+    # docs recommend for playing movies/music). It is a GROUP, not a package,
+    # so it gets its own line — and the loop below sends it to install_group.
+    "@multimedia"
     )
 
 step "6 Always-installed packages"
@@ -421,6 +428,17 @@ rule
 
 always_failed=""
 for category in "${ALWAYS_PACKAGES[@]}"; do
+    # A "@group" line is a dnf comps group. install_group checks the group
+    # exists first and prints the real group list when it does not, instead
+    # of dnf's unhelpful "No match for argument: @multimedia".
+    if [[ "$category" == @* ]]; then
+        if ! install_group "${category#@}"; then
+            color_red "  Failed: group ${category}"
+            always_failed="yes"
+            pause_if_debug
+        fi
+        continue
+    fi
     # shellcheck disable=SC2086
     if ! install_packages $category; then
         color_red "  Failed: $category"