## Why
Remote plugin requests always sent `OAI-Product-Sku: codex`, ignoring the existing `apps_mcp_product_sku` setting.
## What changed
Pass `apps_mcp_product_sku` through plugin configuration and use it for authenticated remote plugin requests, including discovery, search, installation, and sharing. Keep `codex` as the default and include the SKU when comparing remote service configurations.
## Testing
Extend app-server plugin listing and core agent-turn tests to check default and configured SKU headers. Update the CLI worktree test to wait for the user prompt's model request, skipping background title generation requests.
GitOrigin-RevId: 508c9ef9aa3e41b87c92383c3088eb1eb9227fd8