Start-HttpServer

Starts a lightweight static file server using the built-in .NET HttpListener class,
with behavior similar to Python's `python -m http.server` command. No additional
packages or web framework are required.

The server serves files below SiteRoot, returns index.html for directory URLs when
present, and generates a directory listing when no index.html exists. It supports
GET and HEAD requests, common content types, directory redirects, and conditional
caching with Last-Modified and If-Modified-Since. Missing paths and requests that
resolve outside SiteRoot return 404.

By default, the server listens on all network interfaces at port 8000, similar to
Python's http.server. Use LocalOnly to restrict access to this computer at
http://localhost:8000/. LAN access requires an elevated PowerShell session and an
enabled inbound Windows Firewall rule for the selected TCP port.

This script is intended for local development, testing, demonstrations, and quick
file sharing. It is not intended to replace a production web server.