feat(android): implement private Rust storage runtime (#90)

crates/storage/src/mobile_key_transfer.rs

@@ -2,8 +2,8 @@
 
 use std::{collections::BTreeMap, error::Error, fmt, fs, io::Write as _, path::Path};
 
+use crate::atomic_file::TempFile;
 use cap_std::{ambient_authority, fs::Dir};
-use cap_tempfile::TempFile;
 use data_encoding::{BASE64URL_NOPAD, HEXLOWER};
 use sha2::{Digest as _, Sha256};