nextcloud-native, nextcloud-native-git: new packages

Source package built from the release tag and a VCS package following
main, both from :ui:createDistributable - the same jpackage application
image that nextcloud-native-bin repackages from upstream's .deb.

nextcloud-native-git is not version-tracked: its pkgver comes from
pkgver() at build time, so latest_version() reports the snapshot already
in the PKGBUILD and the update run stays a no-op until the packaging
itself changes.

nextcloud-native/pkg.sh

@@ -0,0 +1,56 @@
+# nextcloud-native - Nextcloud Native (https://github.com/Obiente/nc-native),
+# an adaptive native Nextcloud client built with Kotlin/Compose Multiplatform.
+#
+# Source package: the PKGBUILD builds :ui:createDistributable from the release
+# tarball, which is the same jpackage application image upstream wraps into the
+# .deb that nextcloud-native-bin repackages.
+#
+# CONTRIBUTING.md lists an Android SDK, Rust and Node.js as prerequisites, but
+# those cover the mobile target, the Windows Explorer helper and the website.
+# The Linux desktop image builds with JDK 21 alone - verified against
+# v0.1.0-alpha.2 with ANDROID_HOME and ANDROID_SDK_ROOT unset.
+#
+# Release/version handling is identical to nextcloud-native-bin: every upstream
+# release is a prerelease and the list is dominated by per-build nightly-* and
+# rolling channel-* releases, so only the versioned v* tags are packaged, and
+# pkgver drops the hyphen (v0.1.0-alpha.2 -> 0.1.0alpha.2), which pacman sorts
+# older than a later plain 0.1.0, so no epoch is needed. See
+# nextcloud-native-bin/pkg.sh.
+
+UPSTREAM_REPO="Obiente/nc-native"
+
+# Installed in CI (pacman) before the makepkg test build.
+BUILD_DEPS=(jdk21-openjdk python)
+
+latest_tag() {
+  gh api "repos/$UPSTREAM_REPO/releases?per_page=100" \
+    --jq '[.[] | select(.tag_name | test("^v[0-9]"))] | .[0].tag_name'
+}
+
+tag_to_pkgver() {
+  sed 's/^v//; s/-//g'
+}
+
+latest_version() {
+  latest_tag | tag_to_pkgver
+}
+
+# refresh_checksums <version> <pkgbuild-path>
+refresh_checksums() {
+  local ver="$1" pkgbuild="$2"
+  local tag sha
+
+  tag="$(latest_tag)"
+  if [[ "$(tag_to_pkgver <<< "$tag")" != "$ver" ]]; then
+    echo "newest versioned release is $tag, not the requested $ver - try again" >&2
+    return 1
+  fi
+
+  sha="$(curl -sfL "https://github.com/$UPSTREAM_REPO/archive/refs/tags/$tag.tar.gz" \
+    | sha256sum | cut -d' ' -f1)"
+
+  sed -i \
+    -e "s|^_tag=.*|_tag=\"$tag\"|" \
+    -e "s|^sha256sums=.*|sha256sums=('$sha')|" \
+    "$pkgbuild"
+}