feat: put ncp on PATH on both platforms; rename WSL reqs to Windows

Ports the ncp PATH work from upstream. Registering ncp as a shell-profile
function failed three ways on Windows: the default Restricted execution policy
blocks the profile itself, profiles don't exist outside PowerShell (cmd, Win+R,
Task Scheduler), and the self-elevating installer writes the admin's profile.

Windows now ships management/ncp.cmd and the installer appends management\ to
the Machine PATH via [Environment]::SetEnvironmentVariable -- never setx, which
truncates PATH at 1024 chars. A .cmd is exempt from the execution policy.

Linux symlinks /usr/local/bin/ncp -> management/nexus-cli.sh, falling back to
the old .bashrc function when sudo is unavailable.

Also renames requirements-wsl.txt to requirements-windows.txt and purges stale
WSL references, including vite.config.js's dev-server comment and
controlpanel.py's "Check WSLg." error string.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

interface/web/vite.config.js

@@ -4,7 +4,8 @@ import react from '@vitejs/plugin-react'
 // https://vite.dev/config/
 export default defineConfig({
   plugins: [react()],
-  // host: true binds 0.0.0.0 so the Windows browser can reach the dev server
-  // through WSL2 (loopback-only binding isn't reliably forwarded out of WSL).
+  // host: true binds 0.0.0.0 so the dev server is reachable from another
+  // machine on the LAN, not just localhost. Dev-only - production is the built
+  // dist/ served by the backend on :8000.
   server: { host: true },
 })