add docs (#54)

* docs

* updates

* Fix: The handleCopy function fails to handle errors from navigator.clipboard.writeText(), causing unhandled exceptions and misleading UI feedback when clipboard operations fail.

Co-authored-by: ctate <chris@ctate.dev>

* Fix: The benchmark file uses emojis (📊, 🚀, 🔨, 📈, 📋, ✅, ⏱️, ⚠) in console output, violating repository guidelines that forbid emojis in code and output.

Co-authored-by: ctate <chris@ctate.dev>

* Remove benchmark/run.ts from PR

---------

Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>

docs/src/app/installation/page.tsx

@@ -0,0 +1,58 @@
+import { CodeBlock } from "@/components/code-block";
+
+export default function Installation() {
+  return (
+    <div className="max-w-2xl mx-auto px-4 sm:px-6 py-8 sm:py-12">
+      <div className="prose">
+        <h1>Installation</h1>
+
+        <h2>npm (recommended)</h2>
+        <CodeBlock code={`npm install -g agent-browser
+agent-browser install  # Download Chromium`} />
+
+        <h2>From source</h2>
+        <CodeBlock code={`git clone https://github.com/vercel-labs/agent-browser
+cd agent-browser
+pnpm install
+pnpm build
+pnpm build:native
+./bin/agent-browser install
+pnpm link --global`} />
+
+        <h2>Linux dependencies</h2>
+        <p>On Linux, install system dependencies:</p>
+        <CodeBlock code={`agent-browser install --with-deps
+# or manually: npx playwright install-deps chromium`} />
+
+        <h2>Custom browser</h2>
+        <p>
+          Use a custom browser executable instead of bundled Chromium:
+        </p>
+        <ul>
+          <li><strong>Serverless</strong> - Use <code>@sparticuz/chromium</code> (~50MB vs ~684MB)</li>
+          <li><strong>System browser</strong> - Use existing Chrome installation</li>
+          <li><strong>Custom builds</strong> - Use modified browser builds</li>
+        </ul>
+
+        <CodeBlock code={`# Via flag
+agent-browser --executable-path /path/to/chromium open example.com
+
+# Via environment variable
+AGENT_BROWSER_EXECUTABLE_PATH=/path/to/chromium agent-browser open example.com`} />
+
+        <h3>Serverless example</h3>
+        <CodeBlock lang="typescript" code={`import chromium from '@sparticuz/chromium';
+import { BrowserManager } from 'agent-browser';
+
+export async function handler() {
+  const browser = new BrowserManager();
+  await browser.launch({
+    executablePath: await chromium.executablePath(),
+    headless: true,
+  });
+  // ... use browser
+}`} />
+      </div>
+    </div>
+  );
+}