feat: add zeroclaw-robot-kit crate for AI-powered robotics

Standalone robot toolkit providing AI agents with physical world interaction.

Features:
- 6 tools: drive, look, listen, speak, sense, emote
- Multiple backends: ROS2, serial, GPIO, mock
- Independent SafetyMonitor with E-stop, collision avoidance
- Designed for Raspberry Pi 5 + Ollama offline operation
- 55 unit/integration tests
- Complete Pi 5 hardware setup guide

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["."]
+members = [".", "crates/robot-kit"]
 resolver = "2"
 
 [package]