[Planning] Issue Labeling & Routing

## Epic: Issue Labeling & Routing

### Description
Improve the accuracy and coverage of automated issue labeling across repos, establish baseline metrics for label correctness, and determine the right balance between shared labels (for consistent SLA reporting) and repo-specific labels (for local workflows).

### Objective
Create the initial plan for the **Issue Labeling & Routing** 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

The issue names no files, tests, or entry points. Start by defining the scope, success criteria, milestones, dependencies, risks, implementation approach, stakeholders, and owners; completion is an agreed initial plan for the Issue Labeling & Routing epic.

Written by the indexing model from the issue text.