packaging: use [[ for bash tests (SonarCloud S7688) (#1488)

Behaviour-preserving: `[[ ]]` in place of `[ ]` for bash tests (SonarCloud shell:S7688). Every script has a bash shebang; no test uses `-a`/`-o`, escaped parentheses or an unquoted pattern on the right of `=`. `bash -n` passes on each script; the rest is left to CI.

- `packaging/linux/flatpak-bundle.sh` (4)

packaging/linux/flatpak-bundle.sh

@@ -22,7 +22,7 @@ FLATHUB=https://dl.flathub.org/repo/flathub.flatpakrepo
 TEST=1
 OCI=0
 TARBALL=""
-while [ $# -gt 0 ]; do
+while [[ $# -gt 0 ]]; do
   case "$1" in
     --no-test) TEST=0; shift ;;
     --oci) OCI=1; shift ;;
@@ -40,7 +40,7 @@ case "$ARCH" in
 esac
 BASENAME="soundcraft-$VERSION-linux-$ARCH"
 TARBALL="${TARBALL:-$DIST/$BASENAME.tar.gz}"
-[ -f "$TARBALL" ] || { echo "error: $TARBALL not found (run packaging/linux/package.sh --formats tar first)" >&2; exit 1; }
+[[ -f "$TARBALL" ]] || { echo "error: $TARBALL not found (run packaging/linux/package.sh --formats tar first)" >&2; exit 1; }
 for tool in flatpak flatpak-builder; do
   command -v "$tool" >/dev/null || { echo "error: $tool not found (apt install flatpak flatpak-builder librsvg2-common)" >&2; exit 1; }
 done
@@ -51,7 +51,7 @@ WORK="$CARGO_TARGET_DIR/flatpak-bundle"
 rm -rf "$WORK"
 mkdir -p "$WORK/stage"
 tar -xzf "$TARBALL" -C "$WORK/stage" --strip-components=1
-[ -x "$WORK/stage/bin/soundcraft" ] || { echo "error: $TARBALL has no bin/soundcraft" >&2; exit 1; }
+[[ -x "$WORK/stage/bin/soundcraft" ]] || { echo "error: $TARBALL has no bin/soundcraft" >&2; exit 1; }
 cp "$HERE/flatpak/$APP_ID.bundle.yml" "$WORK/$APP_ID.yml"
 
 flatpak remote-add --user --if-not-exists flathub "$FLATHUB"
@@ -70,7 +70,7 @@ if [[ "$OCI" = 1 ]]; then
   echo "wrote OCI layout to $OUT_OCI"
 fi
 
-if [ "$TEST" = 1 ]; then
+if [[ "$TEST" = 1 ]]; then
   flatpak install --user -y --noninteractive --reinstall "$OUT"
   flatpak info --user "$APP_ID"
   flatpak run --command=soundcraft-cli "$APP_ID" --version