feat(agent): change default FS_ROOT to '/' on Unix to fix NAS access ...

- Default FS_ROOT is now '/' instead of '~'.\n- Resolved traversal block for /volume1 paths on Synology.\n- Bumped agent version to 1.0.19.

fix(agent): resolve config path absolutely and ensure correct CWD for background processes

refactor: organize agent-node client code structure by moving core packages to src/ ...

- Moved agent_node, protos, and shared_core inside src/

- Updated Dockerfile, deployment scripts, compile_protos.sh, installers

- Updated bundle generation in ai-hub to reflect cleaner structure and better README