- Add mutex protection for global registry state
- Cache loaded config paths to avoid redundant file reads
- Add ResetRegistryForTesting() for test isolation
- Add BuildResumeCommand() for agent-specific session resume
- Add SupportsSessionResume() and GetSessionIDEnvVar() helpers
Fixes: gt-sn610, gt-otgn3, gt-r2eg1
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implements agent abstraction layer to support multiple AI coding agents.
Built-in presets (E2E tested):
- Claude Code (default)
- Gemini CLI
- OpenAI Codex
Key changes:
- Add AgentRegistry with built-in presets and custom agent support
- Add TownSettings with default_agent and custom agents map
- Add Agent field to RigSettings for per-rig agent selection
- Update ResolveAgentConfig for hierarchical config resolution
- Update spawn paths to use configured agent instead of hardcoded claude
Configuration hierarchy (first match wins):
1. Rig's Runtime config (backwards compat)
2. Rig's Agent -> custom agents -> built-in presets
3. Town's default_agent setting
4. Fallback to Claude
Additional agents (aider, opencode, etc.) can be added via config file:
settings/agents.json
Addresses Issue #10: Agent Agnostic Engine with Multi-provider support
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
