- Add essential draw.io XML structure rules to system prompt
- Include critical rules about mxCell nesting (all must be direct children of root)
- Add shape/vertex and connector/edge examples with proper structure
- Improve tool description for display_diagram with validation rules
- Update xml_guide.md with better swimlane examples showing flat structure
- Add client-side XML validation to catch nested mxCell errors early
Helps address issues #40 (local Ollama models not working) and #39 (mxCell nesting errors)
- Add formatXML function to format single-line XML with proper indentation
- Format chartXml after fetching to ensure consistency
- Update replaceXMLParts to handle single-line XML with substring fallback
- Improve edit_diagram tool guidance with SEARCH/REPLACE best practices
- Add concrete examples to help AI use minimal, targeted edits
