fix: prevent orphaned processes from consuming 100% CPU when terminal closes (#16965)

Co-authored-by: Tommaso Sciortino <sciortino@gmail.com>

packages/cli/src/gemini.tsx

@@ -32,6 +32,8 @@ import {
   registerSyncCleanup,
   runExitCleanup,
   registerTelemetryConfig,
+  setupSignalHandlers,
+  setupTtyCheck,
 } from './utils/cleanup.js';
 import {
   cleanupToolOutputFiles,
@@ -319,6 +321,8 @@ export async function startInteractiveUI(
     });
 
   registerCleanup(() => instance.unmount());
+
+  registerCleanup(setupTtyCheck());
 }
 
 export async function main() {
@@ -340,6 +344,8 @@ export async function main() {
 
   setupUnhandledRejectionHandler();
 
+  setupSignalHandlers();
+
   const slashCommandConflictHandler = new SlashCommandConflictHandler();
   slashCommandConflictHandler.start();
   registerCleanup(() => slashCommandConflictHandler.stop());
@@ -646,10 +652,7 @@ export async function main() {
       process.stdin.setRawMode(true);
 
       // This cleanup isn't strictly needed but may help in certain situations.
-      process.on('SIGTERM', () => {
-        process.stdin.setRawMode(wasRaw);
-      });
-      process.on('SIGINT', () => {
+      registerSyncCleanup(() => {
         process.stdin.setRawMode(wasRaw);
       });
     }