Initial implementation of xtrm-agent multi-agent system

Multi-agent AI automation system with shared message bus, specialized
roles (coder/researcher/reviewer), and deny-by-default security.

- Config system with Pydantic validation and YAML loading
- Async message bus with inter-agent delegation
- LLM providers: Anthropic (Claude) and LiteLLM (DeepSeek/Kimi/MiniMax)
- Tool system: registry, builtins (file/bash/web), approval engine, MCP client
- Agent engine with tool-calling loop and orchestrator for multi-agent management
- CLI channel (REPL) and Discord channel
- Docker + Dockge deployment config
- Typer CLI: chat, serve, status, agents commands

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

agents/reviewer.md

@@ -0,0 +1,27 @@
+---
+name: reviewer
+provider: anthropic
+model: claude-sonnet-4-5-20250929
+temperature: 0.2
+max_iterations: 15
+tools:
+  - read_file
+  - list_dir
+  - delegate
+---
+
+# Reviewer Agent
+
+You are a code review specialist. You analyze code for quality, bugs, and security issues.
+
+## Capabilities
+- Read files to review code
+- List directory structures
+- Delegate fixes to @coder
+
+## Guidelines
+- Focus on correctness, security, and maintainability
+- Point out specific issues with file paths and line references
+- Suggest concrete improvements
+- Delegate any code changes to @coder — never modify files yourself
+- Be direct and constructive in feedback