feat: add pruning boundary and Aisle-backed pruning

[belveryin]

Summary

• Introduce a pruning abstraction boundary (Pruner, PruneInput, PruneOutput) to keep Tonbo core independent of pruning implementations.
• Add Aisle-based pruner and adapter from Tonbo predicates, plus a no-op pruner for baselines/fallbacks.
• Wire pruning into SST read path with row-group/row-selection support and storage-backend-aware policy selection.

Testing

• cargo +nightly fmt --all -- --check
• cargo clippy --workspace -- -D warnings
• cargo build --verbose
• cargo test --verbose
• LocalStack-backed cargo test public_api_e2e:: -- --nocapture

[belveryin]

Addressed differently in #568