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>

browse/test/config.test.ts

@@ -197,6 +197,36 @@ describe('resolveServerScript', () => {
   });
 });
 
+describe('resolveNodeServerScript', () => {
+  const { resolveNodeServerScript } = require('../src/cli');
+
+  test('finds server-node.mjs in dist from dev mode', () => {
+    const srcDir = path.resolve(__dirname, '../src');
+    const distFile = path.resolve(srcDir, '..', 'dist', 'server-node.mjs');
+    const fs = require('fs');
+    // Only test if the file exists (it may not be built yet)
+    if (fs.existsSync(distFile)) {
+      const result = resolveNodeServerScript(srcDir, '');
+      expect(result).toBe(distFile);
+    }
+  });
+
+  test('returns null when server-node.mjs does not exist', () => {
+    const result = resolveNodeServerScript('/nonexistent/$bunfs', '/nonexistent/browse');
+    expect(result).toBeNull();
+  });
+
+  test('finds server-node.mjs adjacent to compiled binary', () => {
+    const distDir = path.resolve(__dirname, '../dist');
+    const distFile = path.join(distDir, 'server-node.mjs');
+    const fs = require('fs');
+    if (fs.existsSync(distFile)) {
+      const result = resolveNodeServerScript('/$bunfs/something', path.join(distDir, 'browse'));
+      expect(result).toBe(distFile);
+    }
+  });
+});
+
 describe('version mismatch detection', () => {
   test('detects when versions differ', () => {
     const stateVersion = 'abc123';