## Summary
- Populate `plugin/list` interface metadata for installed Git-sourced
marketplace plugins from the active cached plugin bundle.
- Preserve marketplace category precedence so list behavior matches
`plugin/read`.
- Keep existing fallback behavior when the cache or manifest is missing
or invalid.
## Test Plan
- `cd codex-rs && just fmt`
- `cd codex-rs && cargo test -p codex-core-plugins
list_marketplaces_installed_git_source_reads_metadata_from_cache_without_cloning`
- `cd codex-rs && cargo test -p codex-app-server
plugin_list_returns_installed_git_source_interface_from_cache`
- `cd codex-rs && just fix -p codex-core-plugins`
- `cd codex-rs && just fix -p codex-app-server`
- `git diff --check`
Server-truth check: OpenAI monorepo app-server generated types already
expose `PluginSummary.interface`, and the webview consumes it for plugin
cards. This PR keeps the protocol/schema unchanged and fills the
existing field from the cached installed bundle for Git-backed
cross-repo plugins.