chore: pinned nats-server download script + gitignore tools/

.gitignore

@@ -25,6 +25,9 @@ dist/
 .env.*.local
 *.log
 
+# Downloaded tooling
+/tools/
+
 # OS
 .DS_Store
 Thumbs.db

scripts/get-nats-server.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# Downloads a pinned nats-server binary to tools/nats-server.
+# Idempotent — skips download if the binary already exists at the pinned version.
+set -euo pipefail
+
+NATS_VERSION="${NATS_VERSION:-v2.10.22}"
+DEST_DIR="$(cd "$(dirname "$0")/.." && pwd)/tools"
+DEST="$DEST_DIR/nats-server"
+
+mkdir -p "$DEST_DIR"
+
+if [ -x "$DEST" ]; then
+  installed=$("$DEST" --version 2>&1 | head -1 | grep -oE 'v[0-9]+\.[0-9]+\.[0-9]+' || echo "unknown")
+  if [ "$installed" = "$NATS_VERSION" ]; then
+    echo "nats-server $NATS_VERSION already installed at $DEST"
+    exit 0
+  fi
+  echo "Replacing $DEST (was $installed) with $NATS_VERSION"
+fi
+
+os=$(uname -s | tr '[:upper:]' '[:lower:]')
+arch=$(uname -m)
+case "$arch" in
+  x86_64|amd64) arch=amd64 ;;
+  aarch64|arm64) arch=arm64 ;;
+  *) echo "unsupported arch: $arch" >&2; exit 1 ;;
+esac
+
+pkg="nats-server-${NATS_VERSION}-${os}-${arch}"
+url="https://github.com/nats-io/nats-server/releases/download/${NATS_VERSION}/${pkg}.tar.gz"
+
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+echo "Downloading $url ..."
+curl -fsSL "$url" -o "$tmp/nats.tgz"
+tar -xzf "$tmp/nats.tgz" -C "$tmp"
+mv "$tmp/$pkg/nats-server" "$DEST"
+chmod +x "$DEST"
+echo "Installed $DEST ($("$DEST" --version | head -1))"