feat: complete clean editor implementation with comprehensive UI framework

Major architectural improvements and feature enhancements:

## Core Features Added
- ✨ Custom status modal system replacing browser alerts with theme-consistent branding
- ✨ HTML generation dogtag with timestamp and username linking
- ✨ All document links now open in new tabs without triggering edit mode
- ✨ Comprehensive UI framework documentation (UserInterfaceFramework.md)

## Architecture Improvements
- 🔧 Complete cleanup of document_manager.py - removed 2000+ lines of legacy code
- 🔧 Clean wrapper implementation maintaining backward compatibility
- 🔧 Enhanced database integration with proper front matter parsing
- 🔧 Improved AST processing and cache file generation

## UI/UX Enhancements
- 🎨 Theme-aware modal dialogs with proper CSS styling and accessibility
- 🎨 Consistent CSS class naming conventions across all UI components
- 🎨 Enhanced link behavior for better document navigation
- 🎨 Professional status information display

## Developer Experience
- 📝 Comprehensive UI component documentation for future development
- 🧪 Updated test suite to work with clean implementation
- 🧪 Fixed multiple test compatibility issues
- 🧪 Enhanced error handling and validation

## Technical Details
- Added store_document method to CleanDocumentManager
- Enhanced ingest_file method with proper title extraction
- Implemented theme-consistent modal overlay patterns
- Added --nodogtag CLI option for clean output when needed
- Fixed CSS escape sequences and JavaScript syntax issues

This release establishes a solid foundation for the clean editor architecture
while maintaining full backward compatibility with existing functionality.

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

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

tests/test_issue_136_index_generation.py

@@ -233,7 +233,7 @@ class TestIndexPageGeneration:
             {"path": self.test_dir / "doc1.html", "title": "Document One", "relative_path": "doc1.html"}
         ]
 
-        html_content = generate_index_html(html_files, "Test Index", template="github")
+        html_content = generate_index_html(html_files, "Test Index", theme="github")
 
         parser = SimpleHTMLParser()
         parser.feed(html_content)