[Planning] Copilot Coding Agent

## Epic: Copilot Coding Agent

### Description
Test whether AI-powered agents can meaningfully assist with initial issue investigation, draft responses, or low-complexity fixes by piloting one narrow use case before deciding on broader investment.

### Objective
Create the initial plan for the **Copilot Coding Agent** epic. This includes:
- Defining scope and success criteria
- Identifying key deliverables and milestones
- Mapping dependencies and risks
- Proposing an implementation approach
- Identifying stakeholders and owners