v3.31.1: the Linux PC/SC headers (pyscard builds from source)

The first release run failed installing the test dependencies:
pyscard 2.3.1 publishes macOS and Windows wheels only (no manylinux),
so on Linux it always builds from source and needs the PC/SC headers -
the job stopped at "winscard.h: No such file or directory".

- The release workflow installs libpcsclite-dev before the dependencies.
- The READMEs and setup.sh name the header package next to pcscd/ccid:
  libpcsclite-dev (Debian/Ubuntu), pcsc-lite-devel (Fedora), included
  in Arch's pcsclite.  This affects every Linux user running setup, not
  just CI.
- Version strings + the PWA cache bumped together (simple-v456).

No runtime change: 997 Python + 953 frontend green; the release package
test builds with the new version.

README.md

@@ -739,7 +739,7 @@ The bundled Python server wraps [pySim](https://osmocom.org/projects/pysim/wiki)
 ### Prerequisites
 
 - **Python 3.9+** with `pip`, and **Git**
-- **Smart card reader** (PC/SC or serial/FTDI) — PC/SC is preferable (`pcsc-lite` + `ccid` on Linux)
+- **Smart card reader** (PC/SC or serial/FTDI) — PC/SC is preferable (`pcsc-lite` + `ccid` on Linux). `pyscard` has no Linux wheels, so it builds from source: install the PC/SC header package too (`libpcsclite-dev` on Debian/Ubuntu, `pcsc-lite-devel` on Fedora; on Arch `pcsclite` includes them).
 - **Windows** — use Python 3.9–3.13 (3.13 recommended): `pyscard` ships precompiled wheels for these versions. On 3.14 it builds from source (needs MSVC C++ Build Tools). The SMPP bridge (`smpp.twisted3`) is intentionally skipped on Windows.
 
 ### Scripts