Reusable run type and initiator schemas on rebalancing runs

Broker API

The run type and initiated_from values on the PortfolioRun schema are now described by the reusable PortfolioRunType and PortfolioRunInitiator component schemas.

• PortfolioRunType covers full_rebalance, partial_liquidation, and invest_cash.
• PortfolioRunInitiator covers system, api, and dashboard.

Accepted and returned values are unchanged.

Affected Endpoints

• GET /v1/rebalancing/runs
• GET /v1/rebalancing/runs/{run_id}