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/2-development/README.md

@@ -0,0 +1,25 @@
+# Development
+
+Developer guide for contributing to Mosaic Stack.
+
+## Chapters
+
+1. **Workflow** — Git workflow, branching strategy, and testing requirements
+2. **Database** — Schema design, migrations, and Prisma usage
+3. **Type Sharing** — Type sharing strategy across the monorepo
+
+## Development Standards
+
+- **Test Coverage:** Minimum 85% for new code
+- **TDD Approach:** Write tests before implementation
+- **Code Style:** Follow Google Style Guides
+- **Type Safety:** Everything must be properly typed
+
+## Prerequisites
+
+Complete the **Getting Started** book before diving into development.
+
+## Next Steps
+
+- Read **Architecture** to understand the system design
+- Review **API** for endpoint conventions