Function default_aqe_optimizer 

pub fn default_aqe_optimizer() -> AqeOptimizer

Default AQE optimizer with guarded coalescing and the streaming guard.

Includes BroadcastRuntimeRule, AutoPartitionRule, CoalesceRule, and SkewJoinRule as guarded rules (skipped for streaming plans). Rules that require runtime statistics will be no-ops until stats feed is wired (see AqeOptimizer::apply).