Add configurable port and directory options for demo command

[robdimarco-atxp]

Summary

• Added configurable port and directory options for the demo command
• Refactored argument parsing logic from run-demo.ts to index.ts for better separation of concerns
• Added comprehensive documentation and examples

Changes

• New option: --port, -p to specify custom demo port (default: 8016)
• New option: --dir, -d to specify custom demo directory (default: ~/.cache/atxp/demo)
• Refactored: Moved CLI argument parsing to index.ts
• Improved: Type safety with DemoOptions interface
• Updated: Help text and README documentation

New Usage Examples

# Use custom port
npx atxp demo --port 3000

# Use custom directory  
npx atxp demo --dir ./my-demo

# Combine options
npx atxp demo --port 9000 --dir ~/projects/demo --verbose

Test plan

• npx atxp shows updated help with new options
• npx atxp demo works with default settings
• --port option allows custom port specification
• --dir option allows custom directory specification
• Path resolution works for relative directories
• All existing functionality preserved (verbose, refresh flags)
• TypeScript compilation successful
• Updated documentation reflects new options

Benefits

• Resolves port conflicts - Users can avoid port 8016 if occupied
• Flexible installation - Users can choose demo location
• Better architecture - Cleaner separation of CLI vs demo logic
• Type safety - Structured options interface
• Backward compatible - All existing usage patterns work

Related to ATXP-243: Allow users to specify what port and working directory to use for the demo

🤖 Generated with Claude Code

[linear]

ATXP-243 Allow users to specify what port and working directory to use