chore: keep the fixture generator scripts and the replay-sample bot

scripts/fixtures/ holds the scripts that produced the 2026-11-11
fixtures, with a README on running them safely into a copy. Run in
order they reproduce the content of every fixture they touch.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

README.md

@@ -151,7 +151,7 @@ fsharp/   src/, solutions/ (with Snake.fsproj), tests/ (Snake.Tests.fsproj, MNN*
           web/            Fable project and browser glue (given), build output; build-web.sh; index.html, pong.html
 scripts/  serve.mjs       a tiny static web server (port 8000) for playing the game
           verify.sh, check-stubs.sh, check-progression.sh, smoke.mjs, check-links.mjs,
-          mutate.mjs (+ mutate-allow.txt), typecheck-js.sh, e2e.sh                    maintainer tools
+          mutate.mjs (+ mutate-allow.txt), typecheck-js.sh, fixtures/ (generators), e2e.sh                    maintainer tools
 e2e/                      maintainer tooling: Playwright end-to-end tests of every track's pages against the JS model
 ```