Cutlass dsl 4.5 bump (#3246)

<!-- .github/pull_request_template.md -->

## 📌 Description

Bump cutlass-dsl to 4.5 so sm121 is supported in BlockScaledMmaOp 

## 🔍 Related Issues

<!-- Link any related issues here -->

## 🚀 Pull Request Checklist

Thank you for contributing to FlashInfer! Before we review your pull
request, please make sure the following items are complete.

### ✅ Pre-commit Checks

- [x] I have installed `pre-commit` by running `pip install pre-commit`
(or used your preferred method).
- [x] I have installed the hooks with `pre-commit install`.
- [x] I have run the hooks manually with `pre-commit run --all-files`
and fixed any reported issues.

> If you are unsure about how to set up `pre-commit`, see [the
pre-commit documentation](https://pre-commit.com/).

## 🧪 Tests

- [x] Tests have been added or updated as needed.
- [x] All tests are passing (`unittest`, etc.).

## Reviewer Notes

<!-- Optional: anything you'd like reviewers to focus on, concerns, etc.
-->


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

* **Chores**
* Updated packaging/install flow to upgrade Python tooling early, added
preparation steps for CUDA/cu13 runtimes, and bumped cutlass dependency
to >=4.5.0; minor project metadata ordering adjusted.

* **Tests**
* Broadened GPU gating to include SM120/SM121 and added CUDA‑13+
detection for gated tests.
* Test harness now installs branch-specific Python requirements during
setup.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Cursor <cursoragent@cursor.com>