Add play.html: the whole game in one file you can open from a disk

[BruceMoseti]

Why

Right now there are two ways to play, and both need something first: the published page needs GitHub Pages switched on (a repository setting no workflow token can set), and make play needs a terminal and a server. There is no way to just open the game.

Double-clicking web/index.html does not work and cannot be made to work: the page is deliberately unbundled plain ES modules, and a browser refuses a module graph over file://. That property is the reason the page needs no toolchain, so it is worth keeping — but it means the repository should ship the one artefact that does open from a disk.

What this is

play.html at the repository root: the same markup, with the stylesheet, the measured figures and all nine modules inlined. 123 kB, no network, no server. Download it and double-click.

play.html opened straight from the filesystem, rendering the full interface

It is a concatenation, not a bundle — no esbuild, no toolchain, in keeping with the rest of web/. That is only legal under three conditions, so web/build/standalone.mjs checks them rather than assuming them: every import is named and static, the graph is acyclic, and no two modules declare the same top-level name. If any stops holding, the build fails naming the offending module and symbol instead of emitting a file that loads and then misbehaves. Renaming imports (canPlaceCue as canPlaceCueAt) become explicit bindings, and import.meta or a dynamic import() anywhere in the graph is rejected outright.

The figures in the prose used to be fetched from web/data/facts.json, which file:// will not read, so the build inlines them into window.__measuredFacts and loadFacts prefers that when present. The served page is unchanged: it still fetches, and its facts still get checked by site_facts.py --check.

How it is kept honest

A stale copy of the game is worse than no copy, so CI does not trust it:

Step	What it catches
standalone.mjs --check	play.html drifting from web/ — rebuilds and compares byte for byte
browser.mjs --url file://…/play.html	the inlined copy failing to load, paint, or finish a game off the disk
input.mjs --url file://…/play.html	pointer capture, the drag threshold and the keyboard breaking under file://

Verified locally: the offline file plays complete games (7 and 11 shots) with no console errors or failed requests, passes 15/15 interaction checks, and the served page still plays clean after the facts.js change. The freshness check was confirmed to fail on a deliberately edited play.html, not just to pass.

make standalone rebuilds it and immediately plays it from a file.

Also here

.gitignore had build/, which was meant for setuptools' ./build but also matched web/build/, where this script lives. Anchored to /build/.

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