Use ipc_channel crate to communicate between cli and app

We still aren't handling CLI requests in the app, but this lays the foundation for bi-directional communication.

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/cli/src/cli.rs

@@ -0,0 +1,21 @@
+pub use ipc_channel::ipc;
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+
+#[derive(Serialize, Deserialize)]
+pub struct IpcHandshake {
+    pub requests: ipc::IpcSender<CliRequest>,
+    pub responses: ipc::IpcReceiver<CliResponse>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum CliRequest {
+    Open { paths: Vec<PathBuf>, wait: bool },
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum CliResponse {
+    Stdout { message: String },
+    Stderr { message: String },
+    Exit { status: i32 },
+}