add packaging script

.gitignore

@@ -1 +1,3 @@
 .env
+package/
+package.tar.zst

package.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+mkdir package
+
+pushd backend
+cargo build --release
+cp -v target/release/nuchat ../package/
+popd
+
+pushd ui
+pnpm run build
+cp -rv .output ../package/ui
+popd
+
+tar -cf - package/ | zstd -19 -T0 -o package.tar.zst
+