Initial codebase migration to public repository

[jcallaham]

Summary

Initial migration of the Lynx project to a public repository. This PR includes the complete working codebase for Lynx, a lightweight block diagram GUI for control systems, along with SpecKit, an integrated feature specification workflow toolkit.

Project Components

Lynx - Block Diagram Widget

Interactive Jupyter widget for creating and editing control system block diagrams using drag-and-drop:

• Core Blocks: Gain, Transfer Function, State Space, Sum Junction, I/O Markers
• LaTeX Rendering: KaTeX-based rendering with auto-scaling and custom LaTeX support
• Visual Features: Simulink-style port markers, editable orthogonal routing, block resizing, theme switching
• Python Integration: Export to python-control for analysis and simulation
• Persistence: Git-friendly JSON format with Pydantic schemas

SpecKit - Feature Development Workflow

Claude Code skills for structured feature development (.claude/commands/speckit.*.md):

• /speckit.specify - Create feature specifications
• /speckit.plan - Generate implementation plans
• /speckit.tasks - Break down into actionable tasks
• /speckit.implement - Execute task lists
• Plus additional tools for clarification, analysis, and GitHub issue generation

Project Status

Features Implemented:

• 15 fully implemented features (001-015)
• 1 partially implemented (016 - documentation infrastructure complete, testing/deployment pending)

Test Suite:

• Python: 407 tests
• Frontend: 310 tests
• Total: 717 tests

Test Coverage:

• Python: 82% overall (key modules: diagram.py 93%, conversion 72-95%, blocks 80-100%)
• Frontend: Comprehensive coverage across all block types and components

Tech Stack:

• Backend: Python 3.11+, anywidget, Pydantic
• Frontend: TypeScript 5.9, React 19.2, React Flow 11.11, Tailwind CSS v4
• Package Management: UV (Python), npm (JavaScript)

Implemented Features (001-015)

1. Core Jupyter Widget - Block library with drag-and-drop interface
2. LaTeX Block Rendering - KaTeX rendering with custom LaTeX support
3. Simulink-Style Port Markers - Connection-aware triangular markers
4. Editable Orthogonal Routing - Interactive edge waypoint editing
5. Hideable Block Labels - Toggle block label visibility
6. Connection Labels - Label edges for signal identification
7. Block Resizing - Interactive corner handle resizing
8. Static Diagram Rendering - Export diagrams to PNG/SVG
9. Collapsible Block Library - Expandable block palette
10. Switchable Themes - Light/dark mode support
11. Sum Quadrant Configuration - Click quadrants to configure signs
12. Python-Control Export - Export diagrams to python-control objects
13. Editable Block Labels - Double-click to edit block labels
14. IOMarker LaTeX Rendering - Automatic index display with Simulink-style renumbering
15. Intelligent Drag Detection - 5-pixel threshold for click vs drag

Changes in This PR

• Complete codebase with all 15 fully implemented features
• Added Jupyter kernel installation instructions to dev/DEV.md
• Project infrastructure: UV environment, testing configuration, CI setup
• Comprehensive documentation in CLAUDE.md and feature specs (16 total)

Test Plan

# Python tests (407 tests)
uv run pytest --cov=lynx

# Frontend tests (310 tests)
cd js && npm test -- --run

# Build verification
./build.sh