next.js example (#694)

* next.js guide

* better

* shadcn

* fixes

* fix: correct screenshot test assertion to check path instead of base64

The daemon returns { path: savePath } for screenshot commands, not base64.

* fix: cross-platform Chrome detection and gitignore hardening

- Replace hardcoded macOS Chrome path with findLocalChrome() that
  searches common paths on macOS, Linux, and WSL, with a clear error
  message when no Chrome is found.
- Add .env and .env*.local to .gitignore to prevent accidental
  secret commits.

* fix: correct Vercel deploy button repo URL to vercel-labs/agent-browser

* clean up

* demo

* next page

---------

Co-authored-by: ctate <366502+ctate@users.noreply.github.com>

examples/demo/scripts/create-snapshot.ts

@@ -0,0 +1,26 @@
+/**
+ * Create a Vercel Sandbox snapshot with agent-browser + Chromium pre-installed.
+ *
+ * Run once:   npx tsx scripts/create-snapshot.ts
+ * Then set:   AGENT_BROWSER_SNAPSHOT_ID=<output id>
+ *
+ * This makes sandbox creation sub-second instead of ~30s.
+ */
+
+import { createSnapshot } from "../lib/agent-browser-sandbox";
+
+async function main() {
+  console.log("Creating Vercel Sandbox with agent-browser + Chromium...");
+  console.log("This takes ~30-60 seconds on first run.\n");
+
+  const snapshotId = await createSnapshot();
+
+  console.log("\nSnapshot created successfully!");
+  console.log(`\n  AGENT_BROWSER_SNAPSHOT_ID=${snapshotId}\n`);
+  console.log("Add this to your .env.local or Vercel environment variables.");
+}
+
+main().catch((err) => {
+  console.error("Failed to create snapshot:", err.message || err);
+  process.exit(1);
+});