docs(dev): add Taskfile and developer documentation

- Add Taskfile.yml with common development tasks
- Add go-task to devbox dependencies
- Create comprehensive README-developer.md covering:
  - Devbox setup and usage
  - Hugo and Docsy basics
  - Task commands reference
  - Development workflow
  - Content creation guide
  - Testing procedures
  - Troubleshooting tips

README-developer.md

@@ -0,0 +1,311 @@
+# Developer Guide - IPCEI-CIS Developer Framework
+
+## 🚀 Quick Start
+
+### Prerequisites
+
+Install [Devbox](https://www.jetify.com/devbox/):
+```bash
+curl -fsSL https://get.jetify.com/devbox | bash
+```
+
+### Setup
+
+1. Clone the repository
+2. Start devbox shell:
+```bash
+devbox shell
+```
+
+Devbox automatically installs all required tools:
+- Hugo (v0.151.0+extended)
+- Go (v1.25.1)
+- Node.js (v24.10.0)
+- Dart Sass
+- htmltest
+- go-task
+
+## 📚 Technology Stack
+
+### Hugo (v0.151.0+extended)
+
+Hugo is a fast static site generator. This project uses Hugo in extended mode with:
+- **Docsy Theme** (v0.12.0) - Documentation theme with responsive design
+- **Bootstrap 5.3.8** - UI framework
+- **PostCSS** - CSS processing
+
+### Docsy Theme
+
+Docsy is a Hugo theme optimized for technical documentation:
+- Multi-language support
+- Search functionality
+- Navigation menu system
+- Code syntax highlighting
+- Responsive design
+
+Key directories:
+- `content/en/` - English content (Markdown files)
+- `layouts/` - Custom layout overrides
+- `assets/scss/` - Custom styles
+- `static/` - Static assets (images, etc.)
+
+### Task (Taskfile)
+
+Task is a task runner / build tool that replaces Makefiles. It uses `Taskfile.yml` for defining tasks.
+
+## 🛠️ Development Workflow
+
+### Using Task (Recommended)
+
+View all available tasks:
+```bash
+task
+# or
+task --list
+```
+
+Common tasks:
+
+#### Development
+```bash
+task serve              # Start Hugo dev server (http://localhost:1313)
+task build              # Build production site
+task build:dev          # Build development site
+task clean              # Clean build artifacts
+```
+
+#### Testing
+```bash
+task test               # Run all tests
+task test:quick         # Run quick tests (without link checking)
+task test:build         # Test if Hugo builds successfully
+task test:markdown      # Lint Markdown files
+task test:html          # Validate HTML output
+task test:links         # Check all links (internal & external)
+```
+
+#### Dependencies
+```bash
+task deps:install       # Install all dependencies
+task deps:update        # Update all dependencies
+```
+
+#### CI/CD
+```bash
+task ci                 # Run full CI pipeline locally
+```
+
+### Using NPM Scripts (Alternative)
+
+If you prefer NPM:
+```bash
+npm test                # All tests
+npm run test:quick      # Quick tests
+npm run test:build      # Build test
+npm run test:markdown   # Markdown linting
+npm run test:html       # HTML validation
+npm run test:links      # Link checking
+```
+
+### Using Hugo Directly
+
+```bash
+# Development server
+hugo server
+
+# Production build
+hugo --gc --minify
+
+# Check version
+hugo version
+```
+
+## 📁 Project Structure
+
+```
+.
+├── content/            # Content files (Markdown)
+│   └── en/            # English content
+│       ├── docs/      # Documentation
+│       └── blog/      # Blog posts
+├── layouts/           # Custom HTML templates
+├── static/            # Static files
+├── assets/            # Assets (SCSS, images)
+├── public/            # Generated site (not in Git)
+├── resources/         # Hugo cache (not in Git)
+├── hugo.toml          # Hugo configuration
+├── go.mod             # Hugo modules (Docsy theme)
+├── Taskfile.yml       # Task definitions
+├── package.json       # NPM dependencies & scripts
+└── devbox.json        # Devbox configuration
+```
+
+## 📝 Content Creation
+
+### Creating New Pages
+
+```bash
+# Using Hugo
+hugo new docs/concepts/my-page.md
+hugo new blog/my-post.md
+
+# Or create manually in content/en/
+```
+
+### Front Matter
+
+Every content file needs front matter:
+
+```yaml
+---
+title: "My Page Title"
+description: "Page description"
+date: 2025-10-23
+weight: 10  # Order in navigation
+---
+
+Your content here...
+```
+
+### Using Docsy Shortcodes
+
+Docsy provides helpful shortcodes:
+
+#### Tabbed Panes
+```markdown
+{{</* tabpane */>}}
+  {{</* tab "Tab 1" */>}}
+  Content for tab 1
+  {{</* /tab */>}}
+  {{</* tab "Tab 2" */>}}
+  Content for tab 2
+  {{</* /tab */>}}
+{{</* /tabpane */>}}
+```
+
+#### Code Blocks
+```markdown
+{{</* code lang="yaml" */>}}
+key: value
+{{</* /code */>}}
+```
+
+#### Alerts
+```markdown
+{{</* alert title="Note" */>}}
+Important information
+{{</* /alert */>}}
+```
+
+## 🧪 Testing
+
+See [TESTING.md](TESTING.md) for detailed testing documentation.
+
+Quick reference:
+- `task test` - Run all tests before committing
+- `task test:quick` - Fast checks during development
+- Tests run automatically on GitHub Actions for PRs
+
+## 🔧 Configuration
+
+### Hugo Configuration (`hugo.toml`)
+
+Main settings:
+- `baseURL` - Site URL
+- `title` - Site title
+- `defaultContentLanguage` - Default language
+- Module imports (Docsy theme)
+
+### Docsy Configuration
+
+Docsy-specific settings in `hugo.toml`:
+```toml
+[params]
+github_repo = "your-repo"
+github_branch = "main"
+```
+
+### Devbox Configuration (`devbox.json`)
+
+Defines all development tools and their versions. 
+
+Update tools:
+```bash
+devbox update          # Update all packages
+task deps:update       # Update all dependencies (devbox + npm + hugo modules)
+```
+
+## 🎨 Styling
+
+Custom styles in `assets/scss/_variables_project.scss`:
+```scss
+// Override Bootstrap/Docsy variables
+$primary: #your-color;
+```
+
+Hugo will process SCSS automatically with PostCSS and Autoprefixer.
+
+## 🌐 Multi-Language Support
+
+Add new language:
+1. Create `content/<lang>/` directory
+2. Add language config in `hugo.toml`:
+```toml
+[languages.<lang>]
+languageName = "Language Name"
+weight = 2
+```
+
+## 🐛 Troubleshooting
+
+### "Module not found" errors
+```bash
+hugo mod get -u
+hugo mod tidy
+```
+
+### PostCSS errors
+```bash
+npm install
+```
+
+### Build errors
+```bash
+task clean
+task build
+```
+
+### Devbox issues
+```bash
+devbox update
+devbox shell --refresh
+```
+
+## 📚 Resources
+
+- [Hugo Documentation](https://gohugo.io/documentation/)
+- [Docsy Documentation](https://www.docsy.dev/docs/)
+- [Taskfile Documentation](https://taskfile.dev/)
+- [Devbox Documentation](https://www.jetify.com/devbox/docs/)
+
+## 🤝 Contributing
+
+1. Create a feature branch
+2. Make your changes
+3. Run tests: `task test`
+4. Commit with semantic messages:
+   - `feat(scope): add new feature`
+   - `fix(scope): fix bug`
+   - `docs(scope): update documentation`
+   - `test(scope): add tests`
+   - `chore(scope): maintenance`
+5. Push and create pull request
+
+## 📦 Deployment
+
+Build for production:
+```bash
+task build
+```
+
+Output will be in `public/` directory, ready for deployment.