Add Justfile and fix server implementation

Server improvements:
- Complete rewrite with robust IPv4/IPv6 support
- Graceful fallback from IPv6 dual-stack to IPv4-only
- Better error handling and informative startup messages
- Proper socket cleanup and server shutdown
- Custom logging with timestamps

Justfile additions:
- serve/serve-bg/stop - Server management
- lint-all/format-all/check-all - Code quality commands
- install/setup/clean - Project management
- validate/info/status - Development helpers
- icons-png/icons-browser - Icon generation
- commit/quick-commit - Git workflow helpers

The server now works reliably across different network configurations
and the justfile provides a comprehensive development workflow.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

justfile

@@ -0,0 +1,138 @@
+# GlitchCraft Development Commands
+# Install just: https://github.com/casey/just
+
+# Default recipe - show available commands
+default:
+    @just --list
+
+# Development server management
+# Start the development server
+serve:
+    python3 server.py
+
+# Start server in background
+serve-bg:
+    python3 server.py &
+    @echo "Server started in background"
+    @echo "Use 'just stop' to stop it"
+
+# Stop background server
+stop:
+    @echo "Stopping GlitchCraft server..."
+    pkill -f "python.*server.py" || echo "No server process found"
+
+# Code quality and linting
+# Lint all JavaScript files
+lint-js:
+    bun run lint:js
+
+# Lint and auto-fix JavaScript
+fix-js:
+    bun run lint:js:fix
+
+# Format all code with Prettier
+format:
+    bun run format
+
+# Check code formatting without modifying files
+check-format:
+    bun run check
+
+# Lint Python code
+lint-python:
+    black --check server.py
+    pylint server.py
+
+# Format Python code
+format-python:
+    black server.py
+
+# Lint and format everything
+lint-all: lint-js lint-python
+    @echo "✓ All linting completed"
+
+# Format everything
+format-all: format-python format
+    @echo "✓ All formatting completed"
+
+# Check everything (linting + formatting)
+check-all: lint-all check-format
+    @echo "✓ All checks passed"
+
+# PWA icon generation
+# Generate PNG icons (requires canvas package)
+icons-png:
+    bun add canvas
+    node app/create-icons.js
+
+# Open browser-based icon generator
+icons-browser:
+    @echo "Opening app/generate-icons.html..."
+    @echo "Right-click each canvas to save icons"
+    python3 -c "import webbrowser; webbrowser.open('app/generate-icons.html')"
+
+# Development workflow
+# Install dependencies
+install:
+    bun install
+
+# Clean up generated files
+clean:
+    rm -rf node_modules/
+    rm -f bun.lockb
+    find . -name "*.pyc" -delete
+    find . -name "__pycache__" -type d -exec rm -rf {} +
+
+# Full setup from scratch
+setup: install icons-png
+    @echo "✓ GlitchCraft setup complete!"
+    @echo "Run 'just serve' to start development"
+
+# Testing and validation
+# Validate HTML files
+validate-html:
+    bunx vnu-jar app/index.html app/generate-icons.html
+
+# Test PWA manifest
+validate-manifest:
+    python3 -m json.tool app/manifest.json > /dev/null && echo "✓ Manifest is valid JSON"
+
+# Run all validations
+validate: validate-html validate-manifest check-all
+    @echo "✓ All validations passed"
+
+# Git helpers
+# Create a commit with all changes
+commit message:
+    git add -A
+    git commit -m "{{message}}\n\n🤖 Generated with [Claude Code](https://claude.ai/code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>"
+
+# Quick commit with lint/format
+quick-commit message: format-all lint-all
+    just commit "{{message}}"
+
+# Development info
+# Show project info
+info:
+    @echo "🎨 GlitchCraft - Artisanal text corruption, served fresh!"
+    @echo ""
+    @echo "📁 Project structure:"
+    @echo "  app/          - Main application (deploy this directory)"
+    @echo "  server.py     - Development server (IPv4/IPv6)"
+    @echo "  justfile      - Development commands"
+    @echo ""
+    @echo "🚀 Quick start:"
+    @echo "  just install  - Install dependencies"
+    @echo "  just serve    - Start development server"
+    @echo "  just check-all - Run all linting and validation"
+    @echo ""
+    @echo "🔗 Server URLs:"
+    @echo "  http://localhost:8000/"
+    @echo "  http://127.0.0.1:8000/     (IPv4)"
+    @echo "  http://[::1]:8000/         (IPv6)"
+
+# Show server status
+status:
+    @echo "Checking server status..."
+    @pgrep -f "python.*server.py" > /dev/null && echo "✓ Server is running" || echo "✗ Server is not running"
+    @echo "Use 'just serve' to start or 'just stop' to stop"