Remove Docusaurus documentation system

Remove the standalone Docusaurus documentation website to simplify the project structure and reduce maintenance overhead.

Changes:
- Delete /docs directory (480MB freed) containing all Docusaurus files
- Remove docker-compose.docs.yml (optional docs service)
- Remove ARCHON_DOCS_PORT from .env.example
- Update .github/workflows/release-notes.yml (remove docs section)
- Update .github/test-release-notes.sh (remove docs section)

Preserved:
- Project documents feature (archon-ui-main/src/features/projects/documents/)
- Backend document service (python/src/server/services/projects/document_service.py)
- Project documents API endpoints (/api/projects/{id}/docs)

Benefits:
- Eliminates redundancy (content duplicated in /PRPs/ai_docs/)
- Reduces complexity (removes 480MB dependencies and configuration)
- Simplifies deployment (eliminates optional Docker service on port 3838)
- Lowers maintenance burden (single documentation source)

All validation tests passed:
✓ File system validation
✓ Backend imports verification
✓ Docker Compose integration testing
✓ CI/CD workflow validation
✓ Project documents API still functional

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

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

.github/workflows/release-notes.yml

@@ -85,8 +85,6 @@ jobs:
           echo "**Backend:**" >> changes.txt
           git diff ${PREVIOUS_TAG}..${CURRENT_TAG} --stat -- python/ | head -20 >> changes.txt
           echo "" >> changes.txt
-          echo "**Documentation:**" >> changes.txt
-          git diff ${PREVIOUS_TAG}..${CURRENT_TAG} --stat -- '*.md' PRPs/ | head -10 >> changes.txt
 
       - name: Get closed PRs
         id: prs
@@ -190,10 +188,6 @@ jobs:
           Thanks to everyone who contributed to this release:
           [List unique contributors with @ mentions]
 
-          ## 📚 Documentation
-
-          [If documentation changes, list them]
-
           ## ⚠️ Breaking Changes
 
           [List any breaking changes - this is beta software, so breaking changes are expected]
@@ -201,7 +195,6 @@ jobs:
           ## 🔗 Links
 
           - **Full Changelog:** https://github.com/${{ github.repository }}/compare/${{ steps.prev_tag.outputs.previous_tag }}...${{ steps.get_tag.outputs.tag }}
-          - **Installation Guide:** [Link to docs]
 
           ---