📚 Expand documentation with autonomous workflows and agent system

Restructured README to emphasize autonomous task execution (`/autotask`),
introduced specialist agents (Dixon, Ada, Phil, Rivera, Petra), and
expanded setup documentation with detailed implementation guides. Reflects
evolution from manual configuration to intelligent automation with
LLM-optimized standards and adaptive agent deployment.

Key improvements:
- Autonomous workflow spotlight with /autotask command
- Named agent introductions (Dixon, Ada, Phil, Rivera, Petra)
- Complete command reference including new commands
- Prompt engineering framework section
- Better structured for quick scanning
- Professional but accessible tone

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

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

Author: Nick Sullivan