## Why
Remote plugin detail responses include MCP server metadata under
`release.mcp_servers`, but Codex did not deserialize or propagate that
field. As a result, `plugin/read` always returned an empty `mcpServers`
list for remote plugins, so the plugin details pane omitted the MCP
Servers section even when the remote plugin declares one.
This affects uninstalled plugins as well: the remote detail API is the
source of truth and returns MCP server keys without requiring a local
plugin bundle.
## What changed
- Deserialize MCP server entries from remote plugin detail responses.
- Normalize their keys into a sorted, deduplicated list on
`RemotePluginDetail`.
- Return those keys from app-server `plugin/read` instead of hardcoding
an empty list.
- Add regression coverage proving an uninstalled remote plugin returns
its MCP server names.
## Test plan
- `just test -p codex-core-plugins`
- `just test -p codex-app-server plugin_read`
Eric NingandGitHub
769c231aa1