feat: add llms.txt standard support for AI agent discoverability (#784)

Cherry-picked website/, scripts/generate-llms-full.sh, and deploy-docs.yml
from joyshmitz's PR. Fixed workflow to trigger on main branch instead of
docs/docusaurus-site.

Features:
- Docusaurus documentation site with llms.txt support
- Environment-variable driven config (defaults to steveyegge org)
- Automated llms-full.txt generation from docs
- GitHub Pages deployment workflow

Co-authored-by: joyshmitz <joyshmitz@users.noreply.github.com>

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Executed-By: beads/crew/dave
Rig: beads
Role: crew

website/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  // This file is not used in compilation. It is here just for a nice editor experience.
+  "extends": "@docusaurus/tsconfig",
+  "compilerOptions": {
+    "baseUrl": "."
+  },
+  "exclude": [".docusaurus", "build"]
+}