fix(cli): prevent Ctrl+D exit when input buffer is not empty (#23306)

Co-authored-by: wtanaka.com <wtanaka@users.noreply.github.com>

packages/cli/src/ui/AppContainer.test.tsx

@@ -2157,13 +2157,8 @@ describe('AppContainer State Management', () => {
         expect(mockHandleSlashCommand).not.toHaveBeenCalled();
 
         pressKey('\x04'); // Ctrl+D
-        // Now count is 2, it should quit.
-        expect(mockHandleSlashCommand).toHaveBeenCalledWith(
-          '/quit',
-          undefined,
-          undefined,
-          false,
-        );
+        // It should still not quit because buffer is non-empty.
+        expect(mockHandleSlashCommand).not.toHaveBeenCalled();
         unmount();
       });
 

packages/cli/src/ui/AppContainer.tsx

@@ -1702,6 +1702,10 @@ Logging in with Google... Restarting Gemini CLI to continue.
         handleCtrlCPress();
         return true;
       } else if (keyMatchers[Command.EXIT](key)) {
+        // If the input field is non-empty, do not exit.
+        if (bufferRef.current.text.length > 0) {
+          return false;
+        }
         handleCtrlDPress();
         return true;
       } else if (keyMatchers[Command.SUSPEND_APP](key)) {