## What changed
- Add the under-development `mcp_oauth_refresh_coordination` feature and pin its selected refresh mode to each MCP connection.
- Treat the refresh mode as part of OAuth connection identity so runtime and MCP configuration refreshes reconnect when the mode changes.
- Keep legacy refresh behavior in builds where coordination is unavailable and emit a warning when coordinated mode is selected.
## Testing
- Cover connection replacement when the feature is toggled through both runtime and MCP configuration refresh paths.
GitOrigin-RevId: 89596150f0338e6ede0e712badecea4450831766