feat(wisp): move backend to managed wisp-server-python

[bgd4141221]

(I think I did a pretty good job also sorry about the commit messages, I forgot to add the "update:" at the beginning of the message)

1. Backend change
   • Replaced in-process @mercuryworkshop/wisp-js/server handling with a proxied, locally managed wisp-server-python.
   • src/server.mjs now:
     • Starts python -m wisp.server when enabled/autostarted.
     • Proxies upgrade requests on the Wisp path to the Python instance via TCP.
     • Handles graceful shutdown and exit signal cleanup.
     • Allows external Wisp endpoints by disabling autostart and pointing host/port to another instance.
2. Configuration
   • New config.json -> wispPython block: enabled, autostart, host, port, allowLoopback, allowPrivate, blockUdp,
     logLevel, proxy, pythonPath.
   • Keeps client-side Wisp URL unchanged; only the backend transport swaps.
3. Tooling & environments
   • Dockerfile installs Python 3 and wisp-python.
   • Devcontainer post-create installs wisp-python.
   • CI (Linux & Windows) installs wisp-python before build/test.
4. Docs
   • TODO item “Implement wisp python…” marked complete.

[QuiteAFancyEmerald]

AI moments.... sorry I cannot merge something like this into the codebase.