Fix duplicate name field and recompile playground workflow

[Copilot]

The playground-assign-to-agent.md workflow had a duplicate name field in the frontmatter that prevented compilation.

Changes:

• Removed duplicate name: Playground Assign to Agent field (line 10) - kept workflow name at line 2
• Recompiled workflow to generate updated .lock.yml file

The frontmatter now correctly defines the workflow name once:

---
name: "Playground: assign-to-agent"
on: 
  workflow_dispatch:
    inputs:
      issue_url:
        description: 'Issue URL to assign agent to...'
        required: true
        type: string
description: Test assign-to-agent safe output feature
permissions:
  contents: read
  issues: read
  pull-requests: read
---

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.