Group A: source upstream binaries instead of self-built artifacts

The AUR does not allow packages to ship a binary tarball built by the
maintainer - a -bin package must repackage a deliverable published by
upstream. These six packages now do that:

  snapx-bin            upstream's self-contained Linux tar.zst
  zapzap-bin           upstream's pure-Python wheel
  faugus-launcher-bin  upstream's arch-independent .deb
  wiiudownloader-bin   upstream's AppImage
  waydroid-helper-bin  upstream's AppImage
  chiaki-ng-bin        upstream's AppImage

All six drop build_artifact() and switch to refresh_checksums(), so CI no
longer builds or hosts anything - it only tracks upstream's assets.

Where the asset name carries build metadata that does not follow from
pkgver (snapx, faugus-launcher), refresh_checksums() resolves it via the
GitHub API and syncs an _asset variable in the PKGBUILD.

Dependency lists are re-derived from what the bundles actually resolve
outside themselves; the AppImage payloads land in /opt with wrappers in
/usr/bin, because their entry points resolve paths relative to argv[0].

snapx-bin/pkg.sh

@@ -1,52 +1,36 @@
 # snapx-bin - SnapX (https://github.com/SnapXL/SnapX), screenshot/sharing
 # tool forked from ShareX, C#/.NET Avalonia UI.
 #
-# Upstream ships a self-contained Linux bundle per (pre)release, but the
-# asset names embed build metadata (e.g. ...-0.4.0-alpha.0+g7eafb0f-X64...)
-# that cannot be derived from the version alone. build_artifact() therefore
-# resolves the asset by pattern via the GitHub API and repackages it under
-# our own predictable name. All upstream releases are marked prerelease, so
-# latest_version() reads the release list instead of /latest.
+# Upstream ships a self-contained Linux bundle per (pre)release which the
+# PKGBUILD installs unchanged. The asset names embed build metadata
+# (e.g. ...-0.4.0-alpha.0+g7eafb0f-X64...) that cannot be derived from the
+# version alone, so refresh_checksums() resolves the asset via the GitHub API
+# and syncs the _asset variable in the PKGBUILD along with the checksums.
+# All upstream releases are marked prerelease, so latest_version() reads the
+# release list instead of /latest.
 
 UPSTREAM_REPO="SnapXL/SnapX"
 
-BUILD_DEPS=()
-
 latest_version() {
   gh api "repos/$UPSTREAM_REPO/releases" --jq '.[0].tag_name' | sed 's/^v//'
 }
 
-# build_artifact <version> <output-file>
-build_artifact() {
-  local ver="$1" outfile="$2"
-  local workdir destdir asset
-  workdir="$(mktemp -d)"
-  destdir="$(mktemp -d)"
+# refresh_checksums <version> <pkgbuild-path>
+refresh_checksums() {
+  local ver="$1" pkgbuild="$2"
+  local asset sha_bin sha_src
 
   asset="$(gh api "repos/$UPSTREAM_REPO/releases/tags/v$ver" --jq '.assets[].name' \
     | grep '^SnapX-UI-Release-Linux-' | grep -v musl | grep -- '-X64\.tar\.zst$')"
   [[ "$(wc -l <<< "$asset")" -eq 1 ]] || { echo "expected exactly one UI asset, got: $asset" >&2; return 1; }
 
-  gh release download "v$ver" -R "$UPSTREAM_REPO" --pattern "$asset" --dir "$workdir"
-  mkdir -p "$destdir/opt/snapx"
-  tar -xf "$workdir/$asset" -C "$destdir/opt/snapx"
-  chmod 755 "$destdir/opt/snapx/snapx-ui"
+  sha_bin="$(curl -sfL "https://github.com/$UPSTREAM_REPO/releases/download/v$ver/$asset" \
+    | sha256sum | cut -d' ' -f1)"
+  sha_src="$(curl -sfL "https://github.com/$UPSTREAM_REPO/archive/refs/tags/v$ver.tar.gz" \
+    | sha256sum | cut -d' ' -f1)"
 
-  # upstream's launcher resolves its own directory, so a symlink from
-  # /usr/bin would break it - use a wrapper instead
-  mkdir -p "$destdir/usr/bin"
-  cat > "$destdir/usr/bin/snapx-ui" << 'EOF'
-#!/bin/sh
-exec /opt/snapx/snapx-ui "$@"
-EOF
-  chmod 755 "$destdir/usr/bin/snapx-ui"
-
-  # desktop file, icons and metainfo from the source tree
-  curl -sfL "https://github.com/$UPSTREAM_REPO/archive/refs/tags/v$ver.tar.gz" | tar -xz -C "$workdir"
-  cp -a "$workdir/SnapX-$ver/packaging/usr/share" "$destdir/usr/"
-
-  tar --zstd --sort=name --owner=0 --group=0 --numeric-owner --mtime='@0' \
-      -cf "$outfile" -C "$destdir" usr opt
-
-  rm -rf "$workdir" "$destdir"
+  sed -i \
+    -e "s|^_asset=.*|_asset=\"$asset\"|" \
+    -e "s|^sha256sums=.*|sha256sums=('$sha_bin' '$sha_src')|" \
+    "$pkgbuild"
 }