Add automated setup system for easy installation

- Add setup.sh interactive wizard for 5-minute setup
- Add INSTALL.md comprehensive installation guide
- Add templates/workflows/ directory with parameterized workflow templates
- Update README.md with prominent Installation section
- Update docs/README.md with installation links

The setup wizard automates:
- Platform selection (Gitea/GitHub)
- Bot configuration
- LLM provider setup
- Workflow file generation
- Configuration file creation

Users can now add OpenRabbit to any repository in under 5 minutes.

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

README.md

@@ -26,6 +26,29 @@ Enterprise-grade AI code review system for **Gitea** and **GitHub** with automat
 
 ---
 
+## 📦 Installation
+
+**Quick Setup (5 minutes):**
+
+```bash
+# Clone OpenRabbit
+git clone https://github.com/YourOrg/openrabbit.git
+cd openrabbit
+
+# Run interactive setup wizard
+./setup.sh
+```
+
+The wizard will generate workflow files, create configuration, and guide you through the remaining steps.
+
+**📖 See [INSTALL.md](INSTALL.md) for:**
+- Detailed installation instructions
+- Manual setup guide
+- Platform-specific differences (Gitea vs GitHub)
+- Troubleshooting common issues
+
+---
+
 ## Quick Start
 
 ### 1. Set Repository/Organization Secrets