feat: reorganize admin settings with tabbed interface and documentation

- Reorganized admin settings into tabbed interface (General, Security, Payment Methods)
- Vertical tabs on desktop, horizontal scrollable on mobile
- Moved Payment Methods from separate menu to Settings tab
- Fixed admin profile reuse and dashboard blocking
- Fixed maintenance mode guard to use AppConfig model
- Added admin auto-redirect after login (admins → /admin, users → /)
- Reorganized documentation into docs/ folder structure
- Created comprehensive README and documentation index
- Added PWA and Web Push notifications to to-do list

docs/README.md

@@ -0,0 +1,86 @@
+# Tabungin Documentation
+
+Welcome to the Tabungin documentation! This guide will help you understand the project structure, features, and development workflow.
+
+## 📚 Documentation Structure
+
+### Features
+Detailed documentation for each feature implementation:
+- [Maintenance Mode](./features/maintenance-mode.md) - System maintenance mode with admin bypass
+- [Admin Auto-Redirect](./features/admin-auto-redirect.md) - Automatic admin routing after login
+- [Admin Profile & Dashboard Blocking](./features/admin-profile-reuse.md) - Profile page reuse and access control
+- [Admin Settings Reorganization](./features/admin-settings-tabs.md) - Tabbed settings interface
+
+### Guides
+Step-by-step guides for common tasks:
+- [Testing Guide](./guides/testing-guide.md) - How to test features
+- [Development Setup](./guides/development-setup.md) - Getting started with development
+
+### Planning
+Project planning and roadmap:
+- [To-Do List](./planning/todo.md) - Upcoming tasks and features
+- [Technical Q&A](./planning/tech-qa.md) - Technical decisions and answers
+
+## 🚀 Quick Start
+
+1. **Clone the repository**
+   ```bash
+   git clone <repository-url>
+   cd Tabungin
+   ```
+
+2. **Install dependencies**
+   ```bash
+   npm install
+   ```
+
+3. **Setup environment**
+   ```bash
+   cp .env.example .env
+   # Edit .env with your configuration
+   ```
+
+4. **Run development servers**
+   ```bash
+   # Terminal 1: API
+   cd apps/api
+   npm run dev
+
+   # Terminal 2: Web
+   cd apps/web
+   npm run dev
+   ```
+
+## 🏗️ Project Structure
+
+```
+Tabungin/
+├── apps/
+│   ├── api/          # NestJS backend
+│   └── web/          # React frontend
+├── docs/             # Documentation
+│   ├── features/     # Feature documentation
+│   ├── guides/       # How-to guides
+│   └── planning/     # Project planning
+└── README.md         # Project overview
+```
+
+## 🔗 Useful Links
+
+- [Main README](../README.md) - Project overview
+- [API Documentation](../apps/api/README.md) - Backend API docs
+- [Web Documentation](../apps/web/README.md) - Frontend docs
+
+## 📝 Contributing
+
+When adding new features:
+1. Create feature documentation in `docs/features/`
+2. Update testing guide if needed
+3. Add to to-do list or mark as complete
+4. Update this index
+
+## 🆘 Need Help?
+
+- Check the [Testing Guide](./guides/testing-guide.md)
+- Review [Technical Q&A](./planning/tech-qa.md)
+- See feature-specific documentation in `docs/features/`