Improve deployment automation and documentation

[krobasky]

  Makefile improvements:
  - Add automatic cleanup of ROLLBACK_COMPLETE stacks before deployment
  - Add automatic SAM deployment bucket creation (one-time account setup)
  - Add automatic API Gateway CloudWatch Logs role creation
  - Add node_modules check and auto-generate schemas in start-frontend
  - Fix test-jwt-aws to use $(AWS_REGION) instead of $AWS_REGION
  - Improve test-jwt-aws with better JWT validation and user info display

  Documentation improvements:
  - Update first-deployment.md to use ${ORG} and ${ENV} shell variables
  - Document automatic account-level resource setup
  - Add authentication testing section with proper examples
  - Users can now set ORG/ENV once and paste all commands without editing

  Add CLAUDE.md with comprehensive project overview for AI assistants

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