v3.31.2

Maintenance release on top of v3.31.1.

• SCP81 TLS-PSK now states its Python requirement. ssl's PSK callbacks
  exist only since Python 3.13, so the listener needs Python 3.13+.
  Below that it raises a clear error instead of an AttributeError, and the
  PSK tests are skipped (they run on 3.13+). The READMEs say so.
• Windows: Python 3.13 is strongly recommended. pyscard has precompiled
  wheels up to 3.13, and on 3.14 pyscard and some pysim dependency wheels are
  not available — they build from source and need MSVC C++ Build Tools.
  setup.bat prints the same guidance, and setup.sh notes the SCP81
  requirement on older Pythons.

Install — release package (recommended): download simple-3.31.2.zip,
unzip it anywhere, run setup (it installs pysim from upstream — git is
required) and then start.

Install — source checkout (development): git clone https://github.com/anttro/simple.git, then ./setup.sh (or setup.bat)
and ./start.sh (or start.bat). The clone is for development or changes
not released yet; the zip is the runtime package.

Requirements: Python 3.9+ for the app, 3.13+ for the SCP81 TLS-PSK
listener; on Windows use Python 3.13.