Function process_engine_config 

pub fn process_engine_config() -> EngineConfig

Process-wide engine defaults read once from FTTS_STAGE_BUDGET_*_MS.

The initial budget names are FTTS_STAGE_BUDGET_SYNTHESIS_MS and FTTS_STAGE_BUDGET_ENROLL_MS. Invalid or zero values retain their documented defaults; configuration errors should never silently create an unbounded stage.