docs: Add docstrings to IPC modules to meet 80% coverage threshold

[wilcorrea]

Summary

CodeRabbit's pre-merge check shows docstring coverage at 20%, which is below the required 80% threshold.

Missing Documentation

Need to add docstrings for:

• ipc.rs:

  • IpcCommand struct
  • IpcResponse struct
  • SocketState struct
  • process_command() function
  • setup() function
  • cleanup() function
  • Helper functions: socket_path(), cleanup_stale_socket(), socket_listener_loop(), handle_client()

• tcp_ipc.rs:

  • TcpSocketState struct
  • setup() function
  • cleanup() function
  • Helper functions: tcp_listener_loop(), handle_client()
  • Module-level documentation explaining TCP IPC purpose and usage

Documentation Guidelines

• Explain the purpose and usage of each function/struct
• Document parameters and return values
• Include examples where appropriate
• Explain the IPC protocol (line-based JSON with IpcCommand → IpcResponse)
• Document security considerations (Unix socket permissions, TCP authentication requirements)
• Explain the relationship between Unix socket (native) and TCP socket (container compatibility)

References

• PR fix(tauri): resolve relative paths and prepare for IPC merge #12 CodeRabbit pre-merge check
• Files: apps/tauri/src-tauri/src/ipc.rs, apps/tauri/src-tauri/src/tcp_ipc.rs