fix(planner): require an SLA source for query-log planning #783

Problem

The standalone query-log constructors call query_log::to_controller_config, which creates default ControllerOptions with accuracy_sla: 0.0. YAML configuration now rejects zero accuracy, but this programmatic path bypasses that validation and consequently runs without an accuracy constraint.

Desired outcome

Define an explicit SLA source for query-log mode, such as required CLI flags, and ensure inferred query groups receive validated values. Alternatively, reject query-log planning until SLA input is available.

Context

Raised during review of #781.