fix(cortex-cli): make export command exit code consistent with other commands

Fixes bounty issue #1550

The export command was using bail!() when no sessions were found, which
results in exit code 1. Other commands like resume, sessions, and stats
print a message and return Ok(()) for the same condition, resulting in
exit code 0. This change makes export consistent with those commands.

Author: factorydroid

cortex-cli/src/export_cmd.rs

@@ -96,7 +96,10 @@ impl ExportCommand {
         // Get session ID - either from arg or interactive picker
         let session_id = match self.session_id {
             Some(id) => id,
-            None => select_session(&cortex_home).await?,
+            None => match select_session(&cortex_home).await? {
+                Some(id) => id,
+                None => return Ok(()),
+            },
         };
 
         // Parse conversation ID
@@ -159,11 +162,12 @@ impl ExportCommand {
 }
 
 /// Select a session interactively.
-async fn select_session(cortex_home: &PathBuf) -> Result<String> {
+async fn select_session(cortex_home: &PathBuf) -> Result<Option<String>> {
     let sessions = list_sessions(cortex_home)?;
 
     if sessions.is_empty() {
-        bail!("No sessions found. Create a session first.");
+        println!("No sessions found. Create a session first.");
+        return Ok(None);
     }
 
     // For non-interactive mode, just pick the most recent
@@ -193,7 +197,7 @@ async fn select_session(cortex_home: &PathBuf) -> Result<String> {
     }
 
     println!("\nUsing most recent session: {}", sessions[0].id);
-    Ok(sessions[0].id.clone())
+    Ok(Some(sessions[0].id.clone()))
 }
 
 /// Derive a title from the session content.