Updated dependencies, Added Hosted mode for Stripe checkout

* chore: bump version to 3.1.0 and update dependencies in package.json, pnpm-lock.yaml, and pnpm-workspace.yaml; enhance billing services with support for hosted checkout page in Stripe integration

* Enhance error handling in billing services to log error messages instead of objects; update documentation for Stripe integration to clarify publishable key requirements based on UI mode.

docs/billing/stripe.mdoc

@@ -31,6 +31,7 @@ NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_test_...
 | `STRIPE_SECRET_KEY` | Server-side API key | Dashboard → Developers → API keys |
 | `STRIPE_WEBHOOK_SECRET` | Webhook signature verification | Generated by Stripe CLI or Dashboard |
 | `NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY` | Client-side key (safe to expose) | Dashboard → Developers → API keys |
+| `STRIPE_UI_MODE` | Checkout UI mode: `embedded_page` (default) or `hosted_page` (optional) | - |
 
 {% alert type="error" title="Never commit secret keys" %}
 Add `STRIPE_SECRET_KEY` and `STRIPE_WEBHOOK_SECRET` to `.env.local` only. Never add them to `.env` or commit them to your repository.
@@ -187,6 +188,21 @@ When deploying to production, configure webhooks in the Stripe Dashboard:
 Webhook URLs must be publicly accessible. Vercel preview deployments with authentication enabled won't work. Test by visiting the URL in an incognito browser window.
 {% /alert %}
 
+## Checkout UI Mode
+
+Stripe supports two checkout UI modes:
+
+- **`embedded_page`** (default): Embeds the checkout form directly in your application as a dialog popup. Requires `NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY`.
+- **`hosted_page`**: Redirects users to a Stripe-hosted checkout page. The publishable key is not required in this mode.
+
+Configure this with the `STRIPE_UI_MODE` environment variable:
+
+```bash
+STRIPE_UI_MODE=hosted_page
+```
+
+If not set, it defaults to `embedded_page`.
+
 ## Free Trials Without Credit Card
 
 Allow users to start a trial without entering payment information: