Function run_forgetting_sweep 

pub async fn run_forgetting_sweep(
    store: &SqliteStore,
    config: &ForgettingConfig,
) -> Result<ForgettingResult, MemoryError>

Execute one full forgetting sweep (SleepGate).

All three phases run inside a single transaction to prevent intermediate state from being visible to concurrent readers.

Returns early (no-op) if config contains out-of-range values, logging a warning. Valid ranges:

• decay_rate in (0.0, 1.0) exclusive
• forgetting_floor in [0.0, 1.0) exclusive upper bound
• sweep_interval_secs >= 60

Errors

Returns an error if any database operation fails.