[Workers] Add tutorial: Live cursors & RPC with Next.js and Durable Objects (#18008)

* add new nextjs durable objects rpc tutorial

* fix: hyperlint-ai suggestions

* fix: address reviewer comments

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

Co-authored-by: hyperlint-ai[bot] <154288675+hyperlint-ai[bot]@users.noreply.github.com>

* fix: address reviewer comments

* fix: use `getWebSockets` method

* fix: durable object bug and simplify client-side code

- Ensured WebSocket ID remains accessible by closing connections after broadcasting.
- Cleaned up `cursor.tsx` by moving the main functions to the top.
- Simplified component logic for easier understanding and maintenance.

* Explicitly mention to use host, add optional RPC step

* Update src/content/docs/workers/tutorials/live-cursors-with-nextjs-rpc-do/index.mdx

Add author details

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Co-authored-by: ToriLindsay <[email protected]>
Co-authored-by: hyperlint-ai[bot] <154288675+hyperlint-ai[bot]@users.noreply.github.com>
Co-authored-by: db-cloudflare <[email protected]>

Author: 4 people