Implement optional Quarto integration for advanced users (sub-task 5.6)

Added comprehensive Quarto integration system for high-quality educational document generation:
- Feature-flagged Quarto integration to maintain optional dependency
- Complete QuartoConverter with system detection and capability assessment
- Support for multiple output formats (HTML, PDF, PowerPoint, Word, Book, Website)
- Educational content-type aware formatting with specialized handling
- Integration with existing export manager and unified interface
- Comprehensive documentation and working examples
- Graceful degradation when Quarto unavailable

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: michael-borck

src-tauri/Cargo.toml

@@ -98,9 +98,10 @@ custom-protocol = ["tauri/custom-protocol"]
 chrome-pdf = ["headless_chrome"]
 wkhtml-pdf = ["wkhtmltopdf"]
 image-processing = ["image"]
+quarto-integration = []
 
 # Full feature set for advanced users
-full = ["chrome-pdf", "wkhtml-pdf", "image-processing"]
+full = ["chrome-pdf", "wkhtml-pdf", "image-processing", "quarto-integration"]
 
 # Development features
 dev = ["tracing/max_level_debug"]

src-tauri/docs/quarto-integration.md

@@ -0,0 +1,307 @@
+# Quarto Integration for Advanced Users
+
+The Curriculum Curator provides optional integration with [Quarto](https://quarto.org), a scientific and technical publishing system that enables creation of high-quality educational documents, presentations, and websites.
+
+## Overview
+
+Quarto is the next-generation version of R Markdown, built on Pandoc, that supports multiple programming languages and output formats. For educational content creators, Quarto offers:
+
+- **Single Source, Multiple Outputs**: Generate HTML, PDF, PowerPoint, and Word documents from one source
+- **Interactive Features**: Code execution, embedded widgets, and dynamic content
+- **Professional Typography**: High-quality typesetting with LaTeX integration
+- **Academic Features**: Citations, cross-references, and bibliographies
+- **Template System**: Customizable templates for institutional branding
+
+## Prerequisites
+
+### System Requirements
+
+1. **Quarto Installation**: Download and install Quarto from [quarto.org](https://quarto.org/docs/get-started/)
+2. **Optional Dependencies** (for enhanced features):
+   - **Python**: For interactive Python code blocks
+   - **R**: For statistical computing and visualization
+   - **Julia**: For high-performance computing
+   - **LaTeX**: For PDF generation (TeXLive or MiKTeX)
+
+### Feature Flag
+
+Quarto integration is disabled by default to avoid requiring Quarto for basic usage. Enable it when building:
+
+```bash
+# Enable Quarto integration only
+cargo build --features quarto-integration
+
+# Enable all advanced features
+cargo build --features full
+```
+
+## Supported Export Formats
+
+The Quarto integration provides these export formats:
+
+| Format | Description | Output | Use Case |
+|--------|-------------|---------|----------|
+| `QuartoHtml` | Interactive HTML | `.html` | Online learning, interactive content |
+| `QuartoPdf` | High-quality PDF | `.pdf` | Print materials, formal documents |
+| `QuartoPowerPoint` | Presentation slides | `.pptx` | Classroom presentations |
+| `QuartoWord` | Word document | `.docx` | Collaborative editing |
+| `QuartoBook` | Multi-chapter book | `.html/.pdf` | Course textbooks, comprehensive guides |
+| `QuartoWebsite` | Multi-page website | `.html` | Course websites, online resources |
+
+## Usage Examples
+
+### Basic Export
+
+```rust
+use curriculum_curator::export::{ExportFormat, ExportOptions, QuartoConverter, FormatConverter};
+
+// Check if Quarto is available
+if QuartoConverter::is_available() {
+    let converter = QuartoConverter::new()?;
+    
+    let options = ExportOptions {
+        format: ExportFormat::QuartoHtml,
+        output_path: PathBuf::from("output.html"),
+        template_name: None,
+        include_metadata: true,
+    };
+    
+    let result = converter.convert(&content, &options).await?;
+}
+```
+
+### Checking Capabilities
+
+```rust
+let converter = QuartoConverter::new()?;
+let capabilities = converter.get_capabilities();
+
+println!("Quarto version: {}", capabilities.version);
+println!("Python support: {}", capabilities.has_python);
+println!("R support: {}", capabilities.has_r);
+```
+
+## Quarto Document Structure
+
+The converter generates `.qmd` files with this structure:
+
+```yaml
+---
+title: "Content Title"
+date: "2024-01-15"
+author: "Curriculum Curator"
+format:
+  html:
+    toc: true
+    toc-location: left
+    code-tools: true
+    theme: cosmo
+  pdf:
+    documentclass: article
+    geometry:
+      - margin=1in
+execute:
+  echo: false
+  warning: false
+---
+
+# Content Title
+
+::: {.callout-note}
+## Content Information
+- **Content Type**: Presentation Slides
+- **Word Count**: 487 words
+- **Estimated Duration**: 90 minutes
+- **Difficulty Level**: Beginner
+:::
+
+## Slide 1
+
+Content here...
+
+::: {.callout-tip collapse="true"}
+## Speaker Notes
+Additional notes for instructors...
+:::
+```
+
+## Content Type Handling
+
+The converter processes different content types optimally for Quarto:
+
+### Slides
+- Converts slide separators to Quarto sections
+- Transforms speaker notes into collapsible callouts
+- Maintains slide hierarchy
+
+### Quizzes
+- Creates interactive question blocks
+- Uses collapsible callouts for answers
+- Formats multiple choice options
+
+### Worksheets
+- Converts exercises to structured sections
+- Creates answer spaces with proper formatting
+- Maintains exercise numbering
+
+### Instructor Notes
+- Organizes content into themed callouts
+- Uses appropriate icons and styling
+- Preserves timing and preparation information
+
+## Template Customization
+
+Quarto supports extensive customization through:
+
+### YAML Configuration
+```yaml
+format:
+  html:
+    theme: custom.scss
+    css: styles.css
+    toc: true
+  pdf:
+    documentclass: book
+    template: custom-template.tex
+```
+
+### Custom Templates
+- Create institutional templates
+- Apply consistent branding
+- Customize typography and layout
+
+### CSS Styling
+- Override default themes
+- Add custom styling
+- Ensure accessibility compliance
+
+## Error Handling
+
+The integration includes robust error handling:
+
+```rust
+match converter.convert(&content, &options).await {
+    Ok(result) => {
+        if result.success {
+            println!("Export successful: {}", result.output_path.display());
+        } else {
+            eprintln!("Export failed: {}", result.error_message.unwrap_or_default());
+        }
+    },
+    Err(e) => {
+        eprintln!("Conversion error: {}", e);
+    }
+}
+```
+
+## Best Practices
+
+### For Educators
+1. **Start Simple**: Begin with basic HTML output, then explore advanced features
+2. **Template Libraries**: Create reusable templates for your institution
+3. **Version Control**: Use Git to track template and content changes
+4. **Batch Processing**: Generate multiple formats simultaneously
+5. **Quality Assurance**: Preview outputs before distribution
+
+### For Developers
+1. **Feature Detection**: Always check if Quarto is available before use
+2. **Graceful Degradation**: Provide fallbacks when Quarto is unavailable
+3. **Resource Management**: Clean up temporary files after processing
+4. **Error Logging**: Log Quarto execution errors for debugging
+5. **Testing**: Test with various content types and formats
+
+## Troubleshooting
+
+### Common Issues
+
+**Quarto Not Found**
+```
+Error: Quarto executable not found
+```
+- Ensure Quarto is installed and in PATH
+- Try specifying full path to quarto executable
+
+**LaTeX Errors (PDF Generation)**
+```
+Error: LaTeX compilation failed
+```
+- Install complete LaTeX distribution (TeXLive/MiKTeX)
+- Check for special characters requiring escaping
+- Use `--debug` flag to see LaTeX output
+
+**Template Errors**
+```
+Error: Template not found
+```
+- Ensure template files are in correct location
+- Check template path in configuration
+- Validate template syntax
+
+### Debug Mode
+
+Enable verbose logging for troubleshooting:
+
+```rust
+// Set environment variable for debug output
+std::env::set_var("QUARTO_DEBUG", "1");
+
+let result = converter.convert(&content, &options).await?;
+```
+
+## Integration with Export Manager
+
+The Quarto converter integrates seamlessly with the existing export system:
+
+```rust
+use curriculum_curator::export::{ExportManager, ExportFormat, ExportOptions};
+
+let manager = ExportManager::new();
+
+// Quarto formats are automatically available if Quarto is installed
+let supported_formats = manager.supported_formats();
+
+// Use through the unified interface
+let result = manager.export_content(&content, &options).await?;
+```
+
+## Performance Considerations
+
+- **Cold Start**: First Quarto execution may be slower due to initialization
+- **Resource Usage**: LaTeX PDF generation is memory-intensive
+- **Batch Processing**: Process multiple documents in sequence for efficiency
+- **Caching**: Quarto caches computations for faster subsequent builds
+
+## Limitations
+
+- **Dependency**: Requires Quarto installation on target system
+- **Complexity**: More complex than basic export formats
+- **File Size**: Generated documents may be larger due to embedded features
+- **Compatibility**: Output quality depends on Quarto version and dependencies
+
+## Future Enhancements
+
+Planned improvements for Quarto integration:
+
+- **Template Marketplace**: Shareable template repository
+- **Live Preview**: Real-time preview during editing
+- **Custom Extensions**: Support for Quarto extensions
+- **Cloud Rendering**: Optional cloud-based rendering service
+- **Multi-language**: Enhanced support for international content
+
+## Resources
+
+- [Quarto Documentation](https://quarto.org/docs/)
+- [Quarto Gallery](https://quarto.org/docs/gallery/)
+- [Template Repository](https://github.com/quarto-dev/quarto-cli/tree/main/src/resources/formats)
+- [Community Templates](https://github.com/topics/quarto-template)
+- [Academic Writing Guide](https://quarto.org/docs/authoring/scholarly-writing.html)
+
+## Contributing
+
+To contribute to Quarto integration:
+
+1. Test with various Quarto versions
+2. Create educational-specific templates
+3. Improve error handling and user experience
+4. Add support for additional Quarto features
+5. Write comprehensive documentation and examples