Epic 125: add bounded streaming end-to-end workflows

[rsasaki0109]

Summary

• add a type-erased, metered bounded streaming pipeline with crop, transform, deterministic voxel, cancellation, sink drain, and JSON receipts
• add spatialrust-stream for local/HTTP point-cloud input and open-ended LAS/LAZ output
• expose the same iterator to Python with cancellation, receipt JSON, stubs, docs, and wheel smoke coverage

Verification

• cargo test --workspace --all-features
• cargo clippy -p spatialrust-pipeline --no-default-features --features pipeline-streaming --lib --tests -- -D warnings
• cargo clippy -p spatialrust --no-default-features --features streaming-cli --bin spatialrust-stream --test streaming_cli -- -D warnings
• cargo check --manifest-path crates/spatialrust-py/Cargo.toml
• maturin build --manifest-path crates/spatialrust-py/Cargo.toml --interpreter python
• extracted-wheel pytest crates/spatialrust-py/tests/test_bindings.py::test_bounded_point_cloud_stream_and_receipt