Configuration for the JNI Rust shim crate emitter (alef-backend-jni).
Most identifiers are derived from the paired [crates.kotlin_android]
section (package, features, etc.). Set crate_dir when the JNI crate
directory should differ from the default <config.name>-jni/ — for
example when config.name carries a language-specific suffix (e.g.
"html-to-markdown-rs") but you want the JNI crate to live at
crates/html-to-markdown-jni/ to match every other binding crate.
When set, the JNI crate is placed at crates/<crate_dir>-jni/ and the
[package] name in the generated Cargo.toml is <crate_dir>-jni.
When unset, both derive from config.name (the default, which matches
the behavior used by alef-backend-jni::gen_shims::jni_output_path).