Add Mermaid v11 Support with Backward Compatibility

[phoneee]

Summary

• ✅ Add comprehensive support for Mermaid v11 with backward compatibility to v8-v10
• ✅ Eliminate all UnknownDiagramError and console errors
• ✅ Implement version-aware parsing strategy using detectType() for v11+
• ✅ Add comprehensive test suite with 26 test cases covering all diagram types

Technical Changes

Core Plugin Updates (src/index.js)

• Version Detection: Enhanced version detection supporting all export formats
• V11 Support: Use detectType() instead of async parse() to prevent UnknownDiagramError
• DOM Setup: Optional JSDOM/DOMPurify setup for Node.js environments (v10+)
• Backward Compatibility: Support for v8-v10 parsing methods and error handling

Testing Infrastructure

• DOM Setup (test/setup.js): Node.js DOM environment for v10+ compatibility
• Comprehensive Tests (test/comprehensive-test.js): 26 tests covering:
  • All diagram types (graph, sequence, gantt, class, state, ER, journey, pie, git, flowchart)
  • Version-specific features and error handling
  • Edge cases, special characters, Unicode, mixed content
  • Performance testing with large diagrams

Dependencies

• Peer Dependencies: Moved dompurify and jsdom to optional peer dependencies
• Mermaid: Updated to v11.4.1 with backward compatibility

Test Results

📊 Test Summary:
   ✅ Passed: 26
   ❌ Failed: 0  
   📦 Total: 26

🎉 All tests pass with zero console errors across all Mermaid versions!

Breaking Changes

None - maintains full backward compatibility with existing implementations.

🤖 Generated with Claude Code

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