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/src/css/custom.css

@@ -0,0 +1,48 @@
+/**
+ * Any CSS included here will be global. The classic template
+ * bundles Infima by default. Infima is a CSS framework designed to
+ * work well for content-centric websites.
+ */
+
+/* You can override the default Infima variables here. */
+:root {
+  --ifm-color-primary: #2e8555;
+  --ifm-color-primary-dark: #29784c;
+  --ifm-color-primary-darker: #277148;
+  --ifm-color-primary-darkest: #205d3b;
+  --ifm-color-primary-light: #33925d;
+  --ifm-color-primary-lighter: #359962;
+  --ifm-color-primary-lightest: #3cad6e;
+  --ifm-code-font-size: 95%;
+  --docusaurus-highlighted-code-line-bg: rgba(0, 0, 0, 0.1);
+}
+
+/* For readability concerns, you should choose a lighter palette in dark mode. */
+[data-theme='dark'] {
+  --ifm-color-primary: #25c2a0;
+  --ifm-color-primary-dark: #21af90;
+  --ifm-color-primary-darker: #1fa588;
+  --ifm-color-primary-darkest: #1a8870;
+  --ifm-color-primary-light: #29d5b0;
+  --ifm-color-primary-lighter: #32d8b4;
+  --ifm-color-primary-lightest: #4fddbf;
+  --docusaurus-highlighted-code-line-bg: rgba(0, 0, 0, 0.3);
+}
+
+/* Center Mermaid diagrams */
+.docusaurus-mermaid-container,
+pre[class*="mermaid"],
+.mermaid,
+[data-theme] .mermaid {
+  display: flex !important;
+  justify-content: center !important;
+  margin: 2rem auto !important;
+  text-align: center;
+}
+
+/* Target the SVG inside mermaid */
+.mermaid svg,
+pre.mermaid svg {
+  max-width: 100%;
+  margin: 0 auto;
+}