[moshiur01]

Two deploy-related changes for the docs app.

Vercel Web Analytics. Adds @vercel/analytics to apps/docs and renders <Analytics /> in the root layout.

Deploy only main. Adds a git.deploymentEnabled rule to apps/docs/vercel.json:

"git": {
  "deploymentEnabled": {
    "**": false,
    "main": true
  }
}

Pushes to any other branch no longer create a preview deployment, so feature branches don't use up Vercel build and deployment limits. Per the Vercel docs, patterns use minimatch and a branch deploys if any matching rule is true, so main still deploys. Checked locally with minimatch: main deploys, while feat/…, fix/…, dev and release/1.0/rc are skipped.

Pull requests won't get preview links anymore. Branches created before this lands keep the old config until they merge main.