Add kernel agents

[grypez]

There is clear semantic alignment between our object capability framework and the relatively recent development of language model tool use, but the tool use interfaces vary across models. Let us:

• Implement a simple feature for acquiring a tool using kernel agent: Add @ocap/kernel-agents package #668
• Support subsequent tool calls Add @ocap/kernel-agents package #668
• Develop a method to format a distributed object as a kernel agent CapabilityRecord
• Add generation error handling