fix(mesh): resolve synology shell bug + bandwidth throttle ...

- Changed mesh-terminal-control to fallback to /bin/sh if bash is missing.\n- Added ~25MB/s bandwidth throttle to Hub/Node file sync to prevent gRPC streaming timeouts.\n- Bumped agent version to 1.0.20.

feat(agent): support FS_ROOT awareness in chat sessions to fix Nas access ...

- Updated Agent to allow out-of-session file access if path is within FS_ROOT.\n- Bumped agent version to 1.0.18.

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