Add check_radicle_cli command

We can check the Radicle home directory to see if the radicle binaries
are installed in the `RAD_HOME` folder

crates/radicle-tauri/src/commands/startup.rs

@@ -42,6 +42,16 @@ pub(crate) fn version(app: AppHandle) -> Result<Version, Error> {
     })
 }
 
+#[tauri::command]
+pub(crate) fn check_radicle_cli(ctx: tauri::State<AppState>) -> Result<(), Error> {
+    let rad = ctx.profile().home().path().join("bin/rad");
+    if !rad.try_exists()? {
+        return Err(Error::RadicleNotInstalled);
+    }
+
+    Ok(())
+}
+
 #[tauri::command]
 pub(crate) fn startup(app: AppHandle) -> Result<Config, Error> {
     let profile = radicle::Profile::load()?;

crates/radicle-tauri/src/lib.rs

@@ -59,6 +59,7 @@ pub fn run() {
             repo::repo_readme,
             startup::startup,
             startup::version,
+            startup::check_radicle_cli,
             thread::create_issue_comment,
             thread::create_patch_comment,
         ])

crates/radicle-types/src/error.rs

@@ -11,6 +11,10 @@ pub enum Error {
     #[error(transparent)]
     ProfileError(#[from] radicle::profile::Error),
 
+    /// Radicle error.
+    #[error("radicle is not installed")]
+    RadicleNotInstalled,
+
     /// Missing SSH Agent error.
     #[error("ssh agent not running")]
     AgentNotRunning,