Feature: Site Build

Purpose

The project contains a static-site input directory (site.in/) and a generated static-site output directory (site.out/).

The Site Build feature provides the script that converts site.in/ into site.out/.

scripts/site-build.sh must generate the static site in site.out/ from the input in site.in/.
Each site.in/*.txt input file must produce site.out/<name>.html.
Every non-.txt, non-template.html file under site.in/ (authored assets such as scripts, styles, and images) must be copied verbatim into site.out/.
The generated ETOPO globe assets (etopo-hypsometric-0.5deg.png and etopo-elevation-0.5deg.json) must be copied from dataflow.out/ into site.out/ when present, so the globe page is self-contained at publish time.
Generated output must be identified as generated.
The script must accept optional input and output directory arguments.
When no arguments are given, the script must use site.in/ and site.out/ relative to the repository root.
The script must be a POSIX shell script.
The HTML page structure must live in site.in/template.html, not in the build script.
site.in/template.html must contain the marker line  where page content is inserted.

Running the script recreates site.out/ from site.in/ (pages and assets).
Re-running the script overwrites existing output deterministically.
The 3D render page (site.in/globe.txt) is built like any other page; it references globe.js and the generated ETOPO assets by relative path.