Add unit tests and documentation for nodeBook parser and renderer

[gnowgi]

Summary

The nodeBook parser (cnl-parser.ts), operations pipeline (operations-to-graph.ts), and renderer (nodebook-graph.tsx) currently have no unit test coverage. Adding tests is critical before building new features on top of the existing infrastructure.

Test Coverage Needed

Parser (cnl-parser.ts)

• Heading parsing: # Name [Type], # **adj** Name [Type], simple headings
• Relation parsing: <relation> target;, multi-target, weighted arcs
• Attribute parsing: values with *unit*, *quantifier*, ++adverb++, [modality]
• Mindmap parsing: # Topic <relation> + - item bullets
• Accounting relations: <debit> → has post_state, <credit> → has prior_state
• Currency directive: currency: USD;
• Edge cases: empty input, malformed headings, missing semicolons

Operations Pipeline (operations-to-graph.ts)

• Three-pass processing: nodes → morphs → edges/attributes
• Morph creation and linkage
• Duplicate node deduplication
• Graph mode detection (mindmap / petri-net / concept-map)

Renderer (nodebook-graph.tsx)

• Snapshot tests for Cytoscape element generation per mode
• Token simulation: initial marking, firing rules, deadlock detection
• Accounting mode: balance computation, equation display, auto-fire

Schema Validation (validate-operations.ts)

• Valid/invalid node types, relation types, attribute types
• User schema overrides via nodeBook-schema

Documentation

• Write tutorials for each graph mode (see sibling issues)
• Document CNL syntax extensions beyond the cheatsheet
• Architecture guide for contributors

Priority

High — prerequisite for safe feature development.