docs: complete documentation for self-directed workflows

- Update agent.md with role fields (role, goal, backstory) and
  DelegationConfig documentation with examples
- Update deployment.md with self-directed workflow platform mappings
  for Claude Code (team_mode, enable_teams) and CrewAI (processType)
- Update overview.md with workflow categories and message types
- Update sdk/go.md with complete API reference including
  CollaborationConfig, Message types, and workflow helpers

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: grokify