patch: typescript 5.9 support (#6877)

Closes #6875

## 🎯 Changes

Adds support for typescript 5.9

## ✅ 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.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
* Updated the TypeScript dependency version from ^5.8.2 to ^5.9.2 across
all example projects and packages.
* Simplified and improved test and type-checking scripts across multiple
packages.
* Added a new type-checking job to the GitHub Actions workflow for pull
requests.
* Enhanced test setup to suppress specific React warnings for cleaner
test output.
* **Bug Fixes**
* Adjusted type definitions to support broader binary data formats in
request bodies.
* Improved type safety with enhanced type predicates for content type
checks.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: KATT

package.json

@@ -27,7 +27,7 @@
     "@types/react": "^19.1.0",
     "@types/react-dom": "^19.1.1",
     "eslint": "^9.26.0",
-    "typescript": "^5.8.2"
+    "typescript": "^5.9.2"
   },
   "version": "11.4.3"
 }