docs: Add docstrings to ipc_common module

[wilcorrea]

Summary

CodeRabbit's pre-merge check shows docstring coverage at 33.33%, below the required 80% threshold. The new ipc_common.rs module needs documentation.

Missing Documentation

Need to add docstrings for:

• Module-level documentation: Explain the purpose of the shared IPC module
• IpcCommand struct: Document the command structure and available commands
• IpcResponse struct: Document the response structure
• process_command() function: Document parameters, return value, and supported commands

Documentation Guidelines

• Explain the purpose and usage of each item
• Document the IPC protocol (line-based JSON with IpcCommand → IpcResponse)
• List supported commands: open, ping, show
• Explain that this module is shared between Unix socket (ipc.rs) and TCP (tcp_ipc.rs) implementations
• Document platform compatibility considerations

Example

//! Shared IPC types and command processing logic.
//!
//! This module contains the common data structures and command handling logic
//! used by both Unix socket IPC (`ipc.rs`) and TCP socket IPC (`tcp_ipc.rs`).
//! It ensures consistent behavior across both communication channels.

/// IPC command sent from external processes.
///
/// Supported commands:
/// - `open`: Open a file in the application (requires `path` field)
/// - `ping`: Check if the application is running
/// - `show`: Bring the application window to the foreground
#[derive(Deserialize)]
pub struct IpcCommand {
    /// The command name
    pub command: String,
    /// Optional file path (required for "open" command)
    #[serde(default)]
    pub path: Option<String>,
}

References

• PR fix(tauri): Extract IPC types to shared module for Windows compatibility #16 CodeRabbit pre-merge check
• File: apps/tauri/src-tauri/src/ipc_common.rs
• Related to issue docs: Add docstrings to IPC modules to meet 80% coverage threshold #15 (IPC module docstrings)