Clarifying developer setup instructions

从 readme.md 中的“Development Environment”部分开始，将其与 README、build64-nvda-addon.sh、非 64 位构建脚本和 .gitignore 进行对比。重现其中所述的 cargo build 和 scons 步骤，然后记录已确认的前置条件、脚本用法以及生成的 Rules 路径。当新贡献者无需面对该 issue 中尚未回答的问题即可设置并构建 addon 时，即视为完成。

Hi, I'm looking to contribute and I've (successfully?) set up a dev environment to build the MathCAT NVDA addon, but ran into a few questions. Once I've confirmed that I didn't do anything wrong, I'll try to update the readme's dev setup instructions with the additional prereqs I encountered.

@NSoiffer

I saw two scripts, build64-nvda-addon.sh and a non-64 counterpart. These files were updated within the past few weeks, possibly implying current use.

1. PYO3_PYTHON_64=C:/Users/neils/AppData/Local/Python/pythoncore-3.13-64
   This path includes neils' username, making this script harder to use off of his machine.

2. I'm more experienced with server-side development, so have more limited familiarity with setting up a Windows build env. This script is a bash script, and while apparently Windows PowerShell allows starting bash these days, it looks like it uses /mnt/C/Users/{username}, not C:/Users/{username}?

I'm unsure how I would run this script, even if I replaced neils' home path with something appropriate to my machine. (Start PowerShell, type bash, then execute the script? Execute directly from PowerShell? Some other terminal or otherwise?)
Are there additional prereqs to run this script on top of the ones covered below? At least build64 seems to point at two different python installs, if I'm reading correctly.

In the end I didn't use this script.

I mostly worked off of https://github.com/daisy/MathCATForPython/tree/main#development-environment

Prereqs approximately following the document:

1. Installed python 3.14.7-64bit via Python installer (instead of 3.11-32bit)
2. Set up venv and installed listed modules
3. Cloned MathCAT and NVDA git repos as siblings to MathCATForPython.

Additional prereqs not covered in that document:

1. Install rust (https://rustup.rs/) and MSVC prereqs. (You call out installing python, so it feels fair to me to call this out as well?)
2. pip install scons. Maybe this one was supposed to be outside the venv, but I installed it in the venv for now.
3. pip install markdown as an additional venv component, since the build seemed to need it?

My build process (no flags, unlike the bash scripts above):

cargo build
scons

Should I have been running any of the flags from the bash scripts?

Also, I've locally added addon/globalPlugins/MathCAT/Rules to the .gitignore file, since cargo build unzips the rules files from the base project into there. Considering that this isn't already in the checked-in .gitignore, am I doing something wrong? Or should I send a PR to update the checked-in file with that?

Also^2, should I fold [README](https://github.com/daisy/MathCATForPython/blob/main/README), which only describes running sconsinto the dev instructions from the more comprehensivereadme.md`?)