chore: eslint updates (#6748)

Closes #

## 🎯 Changes

What changes are made in this PR? Is it a feature or a bug fix?

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## ✅ Checklist

- [ ] I have followed the steps listed in the [Contributing
guide](https://github.com/trpc/trpc/blob/main/CONTRIBUTING.md).
- [ ] If necessary, I have added documentation related to the changes
made.
- [ ] I have added or updated the tests related to the changes made.


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## Summary by CodeRabbit

- **Chores**
- Upgraded ESLint and related linting dependencies across all packages
and examples to their latest versions.
- Updated React and TypeScript ESLint plugins to newer releases,
including the React Hooks plugin.
- Removed deprecated or unused ESLint plugins and configurations in some
packages.

- **Refactor**
- Simplified internal logic using modern JavaScript syntax (nullish
coalescing assignment) in several places for improved readability and
maintainability.
- Adjusted ESLint configurations to streamline plugin integration and
rule management.

- **Style**
- Added or updated ESLint disable comments for new linting rules to
maintain code quality without affecting runtime behavior.

No user-facing features or functionality were changed.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: juliusmarminge

package.json

@@ -26,7 +26,7 @@
     "@types/node": "^22.13.5",
     "@types/react": "^19.1.0",
     "@types/react-dom": "^19.1.1",
-    "eslint": "^9.21.0",
+    "eslint": "^9.26.0",
     "typescript": "^5.8.2"
   },
   "version": "11.1.2"