Add buzz 0.5.28: Block's desktop workspace for humans and agents (#919)

Buzz (https://github.com/block/buzz, Apache-2.0) is a Tauri desktop app
on a Nostr relay. Upstream ships Linux builds for x86_64 only, so this
builds the desktop-v0.5.28 tag from source for x86_64 and aarch64,
following upstream's release-linux job: the six sidecar binaries from
the root workspace, then the app with --features mesh-llm. The updater
stays compiled out (its key and endpoint are unset), so pacman owns
updates. On the fast ring; the watch follows desktop-v* releases.

On aarch64, -march gains +crypto so sha2-asm can assemble its SHA
instructions; sha2 still detects them at runtime.

Built natively for aarch64 with bin/build and launched with isolated
HOME/XDG dirs: the window opens and renders the bundled frontend.

pkgbuilds/buzz/.omarchy/package.json

@@ -0,0 +1,10 @@
+{
+  "source": "local",
+  "release_ring": "fast",
+  "upstream": {
+    "watch": {
+      "github": "block/buzz",
+      "pattern": "desktop-v(?P<version>[0-9]+(?:\\.[0-9]+)*)"
+    }
+  }
+}

pkgbuilds/buzz/PKGBUILD

@@ -0,0 +1,92 @@
+pkgname=buzz
+pkgver=0.5.28
+pkgrel=1
+pkgdesc='Workspace where humans and AI agents build together, on a Nostr relay you own'
+arch=('x86_64' 'aarch64')
+url='https://github.com/block/buzz'
+license=('Apache-2.0')
+
+depends=(
+  'alsa-lib'
+  'cairo'
+  'gcc-libs'
+  'gdk-pixbuf2'
+  'glib2'
+  'glibc'
+  'gst-plugins-good'
+  'gtk3'
+  'hicolor-icon-theme'
+  'libayatana-appindicator'
+  'libsoup3'
+  'opus'
+  'webkit2gtk-4.1'
+)
+makedepends=('cargo' 'cmake' 'nodejs' 'pnpm' 'pkgconf')
+conflicts=('buzz-appimage' 'buzz-bin' 'buzz-desktop-git')
+# Arch's GCC LTO objects cannot be consumed when crates compile bundled C
+# libraries (secp256k1-sys among them).
+options=('!lto')
+
+_srcdir="$pkgname-desktop-v$pkgver"
+source=("$pkgname-$pkgver.tar.gz::$url/archive/refs/tags/desktop-v$pkgver.tar.gz"
+        'buzz.desktop')
+sha256sums=('4ba8c250d6ebb075ba60e6c4d217b77ea605b183161715b77629bd8660b81a43'
+            '3c152420e67c64f5046cc0e10a9d948e1c7d3efa512582ad279f073b0900526a')
+
+# The sidecars the desktop app spawns from its own directory, from upstream's
+# scripts/bundle-sidecars.sh.
+_sidecars=(buzz-acp buzz-agent buzz-backend-kubernetes buzz-dev-mcp git-credential-nostr buzz)
+
+prepare() {
+  cd "$_srcdir"
+
+  export npm_config_store_dir="$srcdir/pnpm-store"
+  pnpm install --frozen-lockfile
+
+  # The sidecars build in the root workspace; the app has its own lockfile.
+  cargo fetch --locked --target "$CARCH-unknown-linux-gnu"
+  cargo fetch --locked --target "$CARCH-unknown-linux-gnu" \
+    --manifest-path desktop/src-tauri/Cargo.toml
+}
+
+build() {
+  cd "$_srcdir"
+
+  export npm_config_store_dir="$srcdir/pnpm-store"
+  # audiopus_sys's vendored opus fallback declares an old CMake minimum.
+  export CMAKE_POLICY_VERSION_MINIMUM=3.5
+  # sha2-asm assembles ARMv8 SHA instructions, which Arch Linux ARM's
+  # -march=armv8-a leaves out. sha2 still checks for them at runtime.
+  [[ $CARCH == aarch64 ]] && CFLAGS=${CFLAGS/-march=armv8-a/-march=armv8-a+crypto}
+
+  cargo build --frozen --release -p buzz-acp -p buzz-agent -p buzz-backend-kubernetes \
+    -p buzz-dev-mcp -p git-credential-nostr -p buzz-cli
+  ./scripts/bundle-sidecars.sh
+
+  # Upstream's Linux release build, without its bundles. Leaving
+  # BUZZ_UPDATER_PUBLIC_KEY and BUZZ_UPDATER_ENDPOINT unset compiles the
+  # self-updater out: pacman owns updates.
+  cd desktop
+  pnpm tauri build --ci --no-bundle --features mesh-llm -- --frozen
+}
+
+package() {
+  cd "$_srcdir"
+
+  install -Dm755 desktop/src-tauri/target/release/buzz-desktop "$pkgdir/usr/bin/buzz-desktop"
+  local bin
+  for bin in "${_sidecars[@]}"; do
+    install -Dm755 "target/release/$bin" "$pkgdir/usr/bin/$bin"
+  done
+
+  install -Dm644 "$srcdir/buzz.desktop" "$pkgdir/usr/share/applications/buzz-desktop.desktop"
+  local icons=desktop/src-tauri/icons size
+  for size in 32 64 128; do
+    install -Dm644 "$icons/${size}x$size.png" \
+      "$pkgdir/usr/share/icons/hicolor/${size}x$size/apps/buzz-desktop.png"
+  done
+  install -Dm644 "$icons/128x128@2x.png" "$pkgdir/usr/share/icons/hicolor/256x256/apps/buzz-desktop.png"
+  install -Dm644 "$icons/icon.png" "$pkgdir/usr/share/icons/hicolor/512x512/apps/buzz-desktop.png"
+
+  install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+}

pkgbuilds/buzz/buzz.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Type=Application
+Name=Buzz
+Comment=Workspace where humans and AI agents build together
+Exec=buzz-desktop %u
+Icon=buzz-desktop
+Terminal=false
+StartupWMClass=buzz-desktop
+Categories=Network;InstantMessaging;Chat;
+MimeType=x-scheme-handler/buzz;