feat: use typescript-eslint@v8 with project service

[JoshuaKGoldberg]

Describe the feature you'd like to request

Following #4540 & coming over from typescript-eslint/typescript-eslint#9141: I'm back again to try out the next typescript-eslint major version on trpc! 🙌

The big new change we have this time is the new project service (parserOptions.projectService). It should result in faster typed linting with an easier configuration.

parserOptions: {
-  project: [
-    // ...
-  ],
+  projectService: true,
  tsconfigRootDir: import.meta.dirname,
},

Describe the solution you'd like to see

I'll send a draft PR with the changes.

Describe alternate solutions

I suppose trpc could stay on typescript-eslint@v6, or use its own bespoke lint configs... neither option seems very appealing to me. 😄

Additional information

No response

👨‍👧‍👦 Contributing

• 🙋‍♂️ Yes, I'd be down to file a PR implementing this feature!