build-node-server.sh — "cannot write multiple output files without an output directory" on fresh install #1010

On a fresh Debian 13 VPS, the bun run build step from gstack/package.json fails in the browse/scripts/build-node-server.sh stage with:

Building Node-compatible server bundle...
error: cannot write multiple output files without an output directory

The error is non-fatal for the overall install (the rest of the setup continues: Playwright Chromium/FFmpeg/Headless Shell downloads, skill linking, gstack ready message), but it's noisy in the terminal and suggests the Node-compat server bundle isn't getting produced.

Environment

• OS: Debian 13 (trixie), x86_64
• bun --version: 1.3.12
• gstack commit: 2300067

Repro

# Fresh Debian 13 VPS as root
curl -fsSL https://bun.sh/install | bash
export PATH="$HOME/.bun/bin:$PATH"
git clone https://github.com/garrytan/gstack.git /tmp/gstack
cd /tmp/gstack
./setup  # observe error during `bun run build`

The failing command (from browse/scripts/build-node-server.sh):

bun build "$SRC_DIR/server.ts" \
  --target=node \
  --outfile "$DIST_DIR/server-node.mjs" \
  --external playwright \
  --external playwright-core \
  --external diff \
  --external "bun:sqlite"

Guess

Bun's --outfile is being treated as conflicting with something (maybe the --external flags make bun think it's a multi-output bundle?). Switching to --outdir + a target-file approach, or running bun build ... > server-node.mjs, might sidestep it.