PeaZip: swap to the wanted flavor when an incompatible one is detected

Per YuKu: instead of skipping when an older flavor is present, SWAP it
to the environment-appropriate one (dnf swap -y old new). Atomic —
if the swap fails, the existing flavor stays and the run continues
with a warning (the safe outcome). Right flavor already present ->
no-op; fresh machine -> plain install.

Verified: qt5+niri -> swap to gtk3 (your laptop scenario); qt6+hyprland
-> no-op; forced swap failure -> warn + keep qt5; fresh -> gtk3.

setup.sh

@@ -640,29 +640,41 @@ rule
 # environments, GTK3 for the rest) ---
 info "Tailoring toolkits for DE=$DE / TWM=$TWM..."
 
-# First: is ANY PeaZip flavor already installed? The UI flavors all ship
-# /usr/bin/peazip and file-conflict with each other — installing gtk3 over
-# an existing qt5 dies mid-transaction (laptop-proven). Any present flavor
-# wins; skipping is correct.
+# The UI flavors all ship /usr/bin/peazip and file-conflict with each
+# other — installing gtk3 over an existing qt5 dies mid-transaction
+# (laptop-proven). Behaviors:
+#   no flavor      -> install the environment-appropriate one
+#   right flavor   -> nothing to do
+#   OTHER flavor   -> dnf SWAP to the wanted one (atomic: on failure the
+#                     existing flavor stays, which is the safe outcome)
+if [[ "$DE" == "plasma" || "$TWM" == "hyprland" ]]; then
+    peazip_wanted="peazip-qt6"
+else
+    # XFCE, GNOME, Niri, MangoWC, chadwm: lightweight/generic toolkits
+    peazip_wanted="peazip-gtk3"
+fi
 peazip_existing=""
 local_v=""
 for local_v in peazip-qt5 peazip-qt6 peazip-gtk3 peazip-gtk2; do
     pkg_installed "$local_v" && peazip_existing="$local_v"
 done
-if [[ -n "$peazip_existing" ]]; then
-    ok "PeaZip already present ($peazip_existing) - skipping."
-else
-    if [[ "$DE" == "plasma" || "$TWM" == "hyprland" ]]; then
-        peazip_pkgs="peazip-common peazip-qt6"
-    else
-        # XFCE, GNOME, Niri, MangoWC, chadwm: lightweight/generic toolkits
-        peazip_pkgs="peazip-common peazip-gtk3"
-    fi
+
+if [[ -z "$peazip_existing" ]]; then
     # shellcheck disable=SC2086
-    if ! install_packages $peazip_pkgs; then
-        color_red "  Failed: $peazip_pkgs"
+    if ! install_packages peazip-common "$peazip_wanted"; then
+        color_red "  Failed: peazip-common $peazip_wanted"
         color_red "  (continuing — PeaZip is a convenience, not a dependency)"
     fi
+elif [[ "$peazip_existing" == "$peazip_wanted" ]]; then
+    ok "PeaZip already present ($peazip_existing)."
+else
+    info "PeaZip $peazip_existing does not match this environment — swapping to $peazip_wanted..."
+    if ui_quiet_run "Swapping PeaZip: $peazip_existing -> $peazip_wanted" \
+        sudo dnf swap -y "$peazip_existing" "$peazip_wanted"; then
+        ok "PeaZip swapped to $peazip_wanted."
+    else
+        warn "Swap failed — keeping the existing $peazip_existing (fully functional)."
+    fi
 fi
 pause_if_debug