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/2-installation/1-prerequisites.md

@@ -0,0 +1,172 @@
+# Prerequisites
+
+Required and optional software for Mosaic Stack development.
+
+## Required
+
+### Node.js 20+
+
+```bash
+# Install using nvm (recommended)
+curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash
+nvm install 20
+nvm use 20
+
+# Verify installation
+node --version  # Should be v20.x.x
+```
+
+### pnpm 9+
+
+```bash
+# Install globally
+npm install -g pnpm@9
+
+# Verify installation
+pnpm --version  # Should be 9.x.x
+```
+
+### PostgreSQL 17+
+
+**Option 1: Native Installation (Linux)**
+
+```bash
+# Ubuntu/Debian
+sudo apt update
+sudo apt install postgresql-17 postgresql-contrib postgresql-17-pgvector
+
+# Start PostgreSQL
+sudo systemctl start postgresql
+sudo systemctl enable postgresql
+
+# Verify installation
+sudo -u postgres psql --version
+```
+
+**Option 2: macOS (Homebrew)**
+
+```bash
+brew install postgresql@17
+brew services start postgresql@17
+```
+
+**Option 3: Docker (Recommended for Development)**
+
+```bash
+# PostgreSQL will be started via docker compose
+# No native installation required
+```
+
+### Git 2+
+
+```bash
+# Ubuntu/Debian
+sudo apt install git
+
+# macOS
+brew install git
+
+# Verify installation
+git --version
+```
+
+## Optional
+
+### Docker & Docker Compose
+
+Required for containerized deployment and recommended for development.
+
+**Linux:**
+
+```bash
+# Install Docker
+curl -fsSL https://get.docker.com -o get-docker.sh
+sudo sh get-docker.sh
+
+# Add user to docker group
+sudo usermod -aG docker $USER
+newgrp docker
+
+# Install Docker Compose
+sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
+sudo chmod +x /usr/local/bin/docker-compose
+
+# Verify installation
+docker --version
+docker compose version
+```
+
+**macOS:**
+
+```bash
+# Install Docker Desktop
+# Download from: https://www.docker.com/products/docker-desktop
+
+# Verify installation
+docker --version
+docker compose version
+```
+
+### Authentik
+
+Required for OIDC authentication in production.
+
+**Docker Installation:**
+
+```bash
+# Download Authentik compose file
+curl -o authentik-compose.yml https://goauthentik.io/docker-compose.yml
+
+# Start Authentik
+docker compose -f authentik-compose.yml up -d
+
+# Access at http://localhost:9000
+```
+
+**Or use an existing Authentik instance**
+
+See [Configuration → Authentik](../3-configuration/2-authentik.md) for setup instructions.
+
+### Ollama
+
+Required for AI features (optional for core functionality).
+
+**Linux:**
+
+```bash
+curl -fsSL https://ollama.com/install.sh | sh
+
+# Pull a model
+ollama pull llama2
+```
+
+**macOS:**
+
+```bash
+brew install ollama
+
+# Pull a model
+ollama pull llama2
+```
+
+**Or use remote Ollama instance**
+
+Configure `OLLAMA_MODE=remote` and `OLLAMA_ENDPOINT` in `.env`.
+
+## Verification
+
+Check all required tools are installed:
+
+```bash
+node --version      # v20.x.x or higher
+pnpm --version      # 9.x.x or higher
+git --version       # 2.x.x or higher
+docker --version    # 24.x.x or higher (if using Docker)
+psql --version      # 17.x.x or higher (if using native PostgreSQL)
+```
+
+## Next Steps
+
+Proceed to:
+- [Local Setup](2-local-setup.md) for native development
+- [Docker Setup](3-docker-setup.md) for containerized deployment