Add manual cross-schema transform test

[shiba4life]

Summary

• add a new integration test that demonstrates manual execution of a transform referencing another schema
• expose the new test module in the integration test suite

Testing

• cargo test --workspace --locked --quiet
• cargo run --manifest-path fold_node/Cargo.toml --example auto_transform_demo
• cargo run --manifest-path fold_node/Cargo.toml --example complex_transform_dsl
• cargo run --manifest-path fold_node/Cargo.toml --example transform_dsl_samples
• cargo run --manifest-path fold_node/Cargo.toml --example transform_logic_test