feat: add documentation website with Docusaurus build pipeline (#1177)

* feat: add documentation website with Docusaurus build pipeline

* feat(docs): add AI discovery meta tags for llms.txt files

- Add global headTags with ai-terms, llms, llms-full meta tags
- Update landing page link to clarify AI context purpose

* fix(docs): restore accidentally deleted faq.md and glossary.md

Files were removed in 12dd97fe during path restructuring.

* fix(docs): update broken project-readme links to GitHub URL

* feat(schema): add compound trigger format validation

test/fixtures/agent-schema/invalid/menu-triggers/compound-invalid-format.agent.yaml

@@ -0,0 +1,24 @@
+# Test: Compound trigger with invalid format
+# Expected: FAIL
+# Error code: custom
+# Error path: agent.menu[0].trigger
+# Error message: agent.menu[].trigger compound format error: invalid compound trigger format
+
+agent:
+  metadata:
+    id: compound-invalid-format
+    name: Invalid Format
+    title: Invalid Format Test
+    icon: 🧪
+
+  persona:
+    role: Test agent
+    identity: Test identity
+    communication_style: Test style
+    principles:
+      - Test principle
+
+  menu:
+    - trigger: TS or tech-spec
+      description: Missing fuzzy match clause
+      action: test