expose checkescape as standalone tool

### Description

Hi, I've just stumbled upon this [thread](https://bsky.app/profile/eatonphil.bsky.social/post/3mpqwjdspek2c) on Bluesky, and I was wondering if you have considered exposing `checkescape` as a standalone tool (or a go-vet tool), or even upstreaming it to the Go compiler itself. It would be really useful for the community if this tool was easier to use.

At the moment, it's wired into the nogo CLI. So one has to write a little wrapper around `checkescape.Analyzer` to run it as a [singlechecker](https://pkg.go.dev/golang.org/x/tools@v0.49.0/go/analysis/singlechecker).

Anyway, thanks for making it public.

### Is this feature related to a specific bug?

_No response_

### Do you have a specific solution in mind?

_No response_

Start with checkescape.Analyzer and its current nogo CLI integration; compare the singlechecker wrapper described in the issue. Before implementation, clarify whether the goal is a standalone tool, a go-vet tool, or Go compiler upstreaming, then define acceptance around invoking checkescape without a custom wrapper.

Written by the indexing model from the issue text.