fix(gui): comprehensive cleanup of child processes on Windows exit (#429)

When quitting the Tauri application on Windows, remaining child processes
were preventing clean exit, causing Windows to prompt to terminate the
command process.

This fix adds comprehensive cleanup in the ExitRequested event handler to
properly terminate all spawned child processes:

- Close all SSH terminal sessions
- Stop all LSP language servers
- Stop all debugger (DAP) sessions
- Disconnect all MCP context servers
- Stop all test watchers
- Stop live metrics monitoring thread
- Shutdown all REPL kernels
- Stop the MCP socket server (debug builds)

Also added a shutdown_all() method to KernelManager for cleaner REPL
kernel shutdown during app exit.

Fixes issue where npm run tauri:dev would leave orphan processes on Windows.

Co-authored-by: Droid Agent <droid@factory.ai>

Author: echobt

cortex-gui/src-tauri/src/lib.rs

@@ -1485,18 +1485,70 @@ pub fn run() {
                         *exiting = true;
                     }
 
+                    info!("Application exit requested, cleaning up all child processes...");
+
                     // Close all terminals when the app exits
                     let terminal_state = app.state::<terminal::TerminalState>();
                     let _ = terminal_state.close_all(app);
                     info!("All terminals closed on app exit");
 
+                    // Close all SSH sessions
+                    let ssh_state = app.state::<ssh_terminal::SSHTerminalState>();
+                    let _ = ssh_state.close_all(app);
+                    info!("All SSH sessions closed on app exit");
+
+                    // Stop all LSP servers
+                    let lsp_state = app.state::<LspState>();
+                    let _ = lsp_state.stop_all_servers();
+                    info!("All LSP servers stopped on app exit");
+
+                    // Stop all debugger sessions
+                    let debugger_state = app.state::<DebuggerState>();
+                    debugger_state.stop_all_sessions();
+                    info!("All debugger sessions stopped on app exit");
+
+                    // Disconnect all MCP context servers
+                    let context_server_state = app.state::<ContextServerState>();
+                    context_server_state.disconnect_all();
+                    info!("All context servers disconnected on app exit");
+
+                    // Stop all test watchers
+                    let test_watcher_state = app.state::<testing::TestWatcherState>();
+                    let _ = test_watcher_state.stop_all();
+                    info!("All test watchers stopped on app exit");
+
+                    // Stop live metrics if running
+                    {
+                        let live_metrics_state = app.state::<Arc<system_specs::LiveMetricsState>>();
+                        live_metrics_state.stop();
+                        info!("Live metrics stopped on app exit");
+                    }
+
+                    // Shutdown all REPL kernels
+                    if let Ok(mut guard) = app.state::<REPLState>().0.lock() {
+                        if let Some(manager) = guard.as_mut() {
+                            manager.shutdown_all();
+                            info!("All REPL kernels shut down on app exit");
+                        }
+                    }
+
+                    // Stop the MCP socket server (debug only)
+                    #[cfg(debug_assertions)]
+                    {
+                        let mcp_state = app.state::<mcp::McpState<tauri::Wry>>();
+                        mcp_state.stop();
+                        info!("MCP socket server stopped on app exit");
+                    }
+
                     // Stop the extension host when the app exits
                     if let Ok(mut manager) = app.state::<ExtensionsState>().0.lock() {
                         if let Some(mut host) = manager.host.take() {
                             host.stop();
                             info!("Extension host stopped on app exit");
                         }
                     }
+
+                    info!("All child processes cleaned up, exiting application");
                 }
                 _ => {}
             }

cortex-gui/src-tauri/src/repl/kernel.rs

@@ -380,6 +380,14 @@ impl KernelManager {
         self.kernels.values().map(|k| k.info.clone()).collect()
     }
 
+    /// Shutdown all running kernels
+    pub fn shutdown_all(&mut self) {
+        let kernel_ids: Vec<String> = self.kernels.keys().cloned().collect();
+        for kernel_id in kernel_ids {
+            let _ = self.shutdown(&kernel_id);
+        }
+    }
+
     /// Get variables from a Python kernel
     pub fn get_variables(&mut self, kernel_id: &str) -> Result<Vec<Variable>, String> {
         let kernel = self