fix(aw-sync): use passed hostname directly instead of client.hostname

- Created push_with_hostname() function that accepts hostname parameter
- Updated JNI functions to use push_with_hostname() with passed hostname
- This ensures sync directory uses actual device name from Android
- Fixes issue where 'localhost' was used despite passing device name

The hostname is now passed directly from Android through JNI to the sync
functions, bypassing the client's hostname entirely.

Author: 0xbrayo