fix: Windows support — Node.js server fallback for Playwright (#255)

* fix: Windows support — Node.js server fallback for Playwright

Setup hangs on Windows 11 because Bun's child_process can't handle
Playwright's --remote-debugging-pipe (fd 3/4 pipe handles). Fall back
to Node.js on Windows for both the setup verification and server
runtime. macOS/Linux completely unaffected — all Windows code behind
IS_WINDOWS / process.platform === 'win32' guards.

Based on community PR #194 by @sozairali. Fixed sed -i portability
(perl -pi -e) in build-node-server.sh for macOS compatibility.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: cross-platform path handling for Windows compatibility

Replace hardcoded '/tmp' and 'dir + "/"' path checks with
platform-aware constants from new platform.ts module. On macOS/Linux
this evaluates identically ('/tmp', '/'); on Windows it uses
os.tmpdir() and path.sep. Zero behavior change on Unix.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: add tests for Windows polyfill, platform constants, and Node server resolution

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: Windows support in README + CHANGELOG (v0.9.1.1)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: bump version and changelog (v0.9.3.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

setup

@@ -12,6 +12,11 @@ GSTACK_DIR="$(cd "$(dirname "$0")" && pwd)"
 SKILLS_DIR="$(dirname "$GSTACK_DIR")"
 BROWSE_BIN="$GSTACK_DIR/browse/dist/browse"
 
+IS_WINDOWS=0
+case "$(uname -s)" in
+  MINGW*|MSYS*|CYGWIN*|Windows_NT) IS_WINDOWS=1 ;;
+esac
+
 # ─── Parse --host flag ─────────────────────────────────────────
 HOST="claude"
 while [ $# -gt 0 ]; do
@@ -44,10 +49,19 @@ elif [ "$HOST" = "codex" ]; then
 fi
 
 ensure_playwright_browser() {
-  (
-    cd "$GSTACK_DIR"
-    bun --eval 'import { chromium } from "playwright"; const browser = await chromium.launch(); await browser.close();'
-  ) >/dev/null 2>&1
+  if [ "$IS_WINDOWS" -eq 1 ]; then
+    # On Windows, Bun can't launch Chromium due to broken pipe handling
+    # (oven-sh/bun#4253). Use Node.js to verify Chromium works instead.
+    (
+      cd "$GSTACK_DIR"
+      node -e "const { chromium } = require('playwright'); (async () => { const b = await chromium.launch(); await b.close(); })()" 2>/dev/null
+    )
+  else
+    (
+      cd "$GSTACK_DIR"
+      bun --eval 'import { chromium } from "playwright"; const browser = await chromium.launch(); await browser.close();'
+    ) >/dev/null 2>&1
+  fi
 }
 
 # 1. Build browse binary if needed (smart rebuild: stale sources, package.json, lock)
@@ -87,10 +101,32 @@ if ! ensure_playwright_browser; then
     cd "$GSTACK_DIR"
     bunx playwright install chromium
   )
+
+  if [ "$IS_WINDOWS" -eq 1 ]; then
+    # On Windows, Node.js launches Chromium (not Bun — see oven-sh/bun#4253).
+    # Ensure playwright is importable by Node from the gstack directory.
+    if ! command -v node >/dev/null 2>&1; then
+      echo "gstack setup failed: Node.js is required on Windows (Bun cannot launch Chromium due to a pipe bug)" >&2
+      echo "  Install Node.js: https://nodejs.org/" >&2
+      exit 1
+    fi
+    echo "Windows detected — verifying Node.js can load Playwright..."
+    (
+      cd "$GSTACK_DIR"
+      # Bun's node_modules already has playwright; verify Node can require it
+      node -e "require('playwright')" 2>/dev/null || npm install --no-save playwright
+    )
+  fi
 fi
 
 if ! ensure_playwright_browser; then
-  echo "gstack setup failed: Playwright Chromium could not be launched" >&2
+  if [ "$IS_WINDOWS" -eq 1 ]; then
+    echo "gstack setup failed: Playwright Chromium could not be launched via Node.js" >&2
+    echo "  This is a known issue with Bun on Windows (oven-sh/bun#4253)." >&2
+    echo "  Ensure Node.js is installed and 'node -e \"require('playwright')\"' works." >&2
+  else
+    echo "gstack setup failed: Playwright Chromium could not be launched" >&2
+  fi
   exit 1
 fi