feat: guide AI agents to the fewest files

llms.txt and an ARD manifest name the pages and the JSON API, and lead
an agent setting up a device to --for-games --required-only. Every page
registers four read-only WebMCP tools: the setup command, a hash lookup,
an emulator's files and the site search.

.github/workflows/deploy-site.yml

@@ -45,6 +45,7 @@ on:
       - "scripts/restore_large_files.py"
       - "scripts/safeparse.py"
       - "scripts/sect233r1.py"
+      - "scripts/siteagents.py"
       - "scripts/sitebootstrap.py"
       - "scripts/sitediagrams.py"
       - "scripts/siteentries.py"