feat(desktop): add flatpak and arch packaging inputs (#2838)

fluxer_desktop/packaging/linux/build-flatpak.sh

@@ -0,0 +1,33 @@
+#!/bin/sh
+# SPDX-License-Identifier: AGPL-3.0-or-later
+set -eu
+
+: "${FLATPAK_APP_ID:?FLATPAK_APP_ID must be set}"
+: "${FLATPAK_TARGET_ARCH:?FLATPAK_TARGET_ARCH must be set}"
+: "${FLATPAK_RUNTIME_BRANCH:?FLATPAK_RUNTIME_BRANCH must be set}"
+: "${HOST_UID:?HOST_UID must be set}"
+: "${HOST_GID:?HOST_GID must be set}"
+
+dnf install -y --setopt=install_weak_deps=False flatpak flatpak-builder
+
+flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
+flatpak install -y --noninteractive --arch="${FLATPAK_TARGET_ARCH}" flathub \
+	"org.freedesktop.Platform//${FLATPAK_RUNTIME_BRANCH}" \
+	"org.freedesktop.Sdk//${FLATPAK_RUNTIME_BRANCH}" \
+	"org.electronjs.Electron2.BaseApp//${FLATPAK_RUNTIME_BRANCH}"
+
+cd /build
+rm -rf repo builddir .fb-state
+
+flatpak-builder \
+	--arch="${FLATPAK_TARGET_ARCH}" \
+	--repo=repo \
+	--force-clean \
+	--disable-rofiles-fuse \
+	--state-dir=.fb-state \
+	builddir "${FLATPAK_APP_ID}.yml"
+
+rm -rf builddir .fb-state
+ostree --repo=repo refs
+rm -rf repo/tmp repo/state repo/extensions repo/.lock
+chown -R "${HOST_UID}:${HOST_GID}" repo