`/agent` fails to parse agent.md `infer` YAML frontmatter property

[JeffreyCA]

Describe the bug

The repo I work in has a couple of custom agents .md files defined in .github/agents/ with the following YAML frontmatter block:

---
name: Agent Name
description: Agent description
infer: true
---

When I run /agent, it fails with:

✗ No available custom agents:
   • /path/.github/agents/1.agent.md: infer: Expected boolean, received string
   • /path/.github/agents/2.agent.md: infer: Expected boolean, received string
   To learn how to create custom agents, visit:
   https://docs.github.com/en/copilot/how-tos/use-copilot-agents/use-copilot-cli#use-custom-agents

Affected version

0.0.389-1

Steps to reproduce the behavior

1. Setup project with custom agents with infer YAML frontmatter property set to true or false
2. Start copilot
3. Run /agent command

Expected behavior

/agent should successfully parse custom agent files.

Additional context

No response