Adding the id of the plugin that contains the MCP (if any) so we can
apply filters at plugin level.
## Summary
- carry the plugin owner into MCP runtime provenance
- attach `plugin_id` to outbound plugin-backed MCP tool-call `_meta`
- avoid misattributing user-configured MCP servers that shadow plugin
server names
## Testing
- `just fmt`
- `just fix -p codex-mcp`
- `just fix -p codex-core`
- `cargo test -p codex-mcp`
- `cargo test -p codex-core
plugin_mcp_tool_call_request_meta_includes_plugin_id`
- `cargo test -p codex-core
to_mcp_config_omits_plugin_id_when_user_server_shadows_plugin_mcp`
- `cargo test -p codex-core
rebuild_preserving_session_layers_refreshes_plugin_derived_mcp_config`
- `git diff --check`
## Notes
- Attempted `cargo test -p codex-core`; it aborted in
`agent::control::tests::resume_agent_from_rollout_skips_descendants_when_parent_resume_fails`
with a stack overflow before the full suite completed.
a66e0e9c4b