Mermaid Fix

Fixes Mermaid diagram parsing errors using mermaid-cli and discovers new rules.

Quick Start

1. Read existing rules: Load .claude/rules/mermaid.md for known patterns
2. Extract diagrams: Find all Mermaid code blocks in the target file(s)
3. Validate with mmdc: Run mmdc -i <temp_file> -o /dev/null to check syntax
4. Fix errors: Apply fixes based on mmdc error output
5. Update rules: Add newly discovered error patterns to mermaid.md

Validation Command

# Create temp file, validate, check exit code
mmdc -t neutral -i diagram.mmd -o /dev/null
# Exit code 0 = valid, non-zero = error