🐛 Abort background tasks on Studio exit to prevent hanging

StudioApp now tracks background task handles and aborts them in a Drop
implementation. This ensures the companion loading task and any other
spawned tasks are properly cleaned up when the TUI exits, preventing
the application from hanging while waiting for background work to
complete.

Author: hyperb1iss

src/studio/app/mod.rs

@@ -158,6 +158,8 @@ pub struct StudioApp {
     last_click: Option<(std::time::Instant, u16, u16)>,
     /// Drag selection start info (panel, line number) for code view selection
     drag_start: Option<(PanelId, usize)>,
+    /// Background task handles to abort on exit
+    background_tasks: Vec<tokio::task::JoinHandle<()>>,
 }
 
 impl StudioApp {
@@ -192,6 +194,7 @@ impl StudioApp {
             explicit_mode_set: false,
             last_click: None,
             drag_start: None,
+            background_tasks: Vec::new(),
         }
     }
 
@@ -805,7 +808,7 @@ impl StudioApp {
     }
 
     /// Load companion service asynchronously for fast TUI startup
-    fn load_companion_async(&self) {
+    fn load_companion_async(&mut self) {
         let Some(repo) = &self.state.repo else {
             return;
         };
@@ -816,7 +819,7 @@ impl StudioApp {
             .get_current_branch()
             .unwrap_or_else(|_| "main".to_string());
 
-        tokio::spawn(async move {
+        let handle = tokio::spawn(async move {
             let result = tokio::task::spawn_blocking(move || {
                 use crate::companion::{BranchMemory, CompanionService};
                 use super::state::CompanionSessionDisplay;
@@ -865,6 +868,9 @@ impl StudioApp {
                 }
             }
         });
+
+        // Store handle so we can abort on exit
+        self.background_tasks.push(handle);
     }
 
     /// Run the TUI application
@@ -2600,6 +2606,15 @@ pub enum ExitResult {
     Error(String),
 }
 
+impl Drop for StudioApp {
+    fn drop(&mut self) {
+        // Abort all background tasks to prevent hanging on exit
+        for handle in self.background_tasks.drain(..) {
+            handle.abort();
+        }
+    }
+}
+
 // ═══════════════════════════════════════════════════════════════════════════════
 // Public Entry Point
 // ═══════════════════════════════════════════════════════════════════════════════