docs: Restructure documentation with Bookstack-compatible hierarchy

- Organized docs into numbered shelf/book/chapter/page structure
- Created comprehensive README.md with project overview
- Added Getting Started book (quick start, installation, configuration)
- Added Development book (workflow, testing, type sharing)
- Added Architecture book (design principles, PDA-friendly patterns)
- Added API Reference book (conventions, authentication)
- Moved TYPE-SHARING.md to proper location
- Updated all cross-references in main README
- Created docs/README.md as master index
- Removed old QA automation reports
- Removed deprecated SETUP.md (content split into new structure)

Documentation structure follows Bookstack best practices:
- Numbered books: 1-getting-started, 2-development, 3-architecture, 4-api
- Numbered chapters and pages for ordering
- Clear hierarchy and navigation
- Cross-referenced throughout

Complete documentation available at: docs/README.md

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

docs/1-getting-started/README.md

@@ -0,0 +1,23 @@
+# Getting Started
+
+Complete guide to getting Mosaic Stack installed and configured.
+
+## Chapters
+
+1. **Quick Start** — Get up and running in 5 minutes
+2. **Installation** — Detailed installation instructions for different environments
+3. **Configuration** — Environment setup and authentication configuration
+
+## Prerequisites
+
+Before you begin, ensure you have:
+- Node.js 20+ and pnpm 9+
+- PostgreSQL 17+ (or Docker)
+- Basic familiarity with TypeScript and NestJS
+
+## Next Steps
+
+After completing this book, proceed to:
+- **Development** — Learn the development workflow
+- **Architecture** — Understand the system design
+- **API** — Explore the API documentation