pcscd: auto exit when not in use

fixes `libusb` being busy when app is closed and started again.
```
starting pcscd with /tmp/.mount_StatusKDpnfI/usr/bin/pcscd -f &
00000000 [136864157226944] ccid_usb.c:672:OpenUSBByName() Can't claim interface 3/5: LIBUSB_ERROR_BUSY
00000172 [136864157226944] ifdhandler.c:160:CreateChannelByNameOrChannel() failed
00000003 [136864157226944] ../src/readerfactory.c:1132:RFInitializeReader() Open Port 0x200000 Failed (usb:058f/9540:libudev:0:/dev/bus/usb/003/005)
00000003 [136864157226944] ../src/readerfactory.c:371:RFAddReader() Alcor Micro AU9540 init failed.
00000043 [136864157226944] ../src/hotplug_libudev.c:517:HPAddDevice() Failed adding USB device: Alcor Micro AU9540
qt.core.qobject.connect: QObject::connect(QObject, Unknown): invalid nullptr parameter
```

https://man.freebsd.org/cgi/man.cgi?query=pcscd&sektion=8&manpath=freebsd-release-ports#end

<img width="713" height="153" alt="Screenshot 2025-09-04 at 12 11 18 PM" src="https://github.com/user-attachments/assets/78aa1104-7791-4e6e-9a7f-391466b089d2" />

fixes: #18635

Author: siddarthkay

AppRun

@@ -20,7 +20,7 @@ export PCSCLITE_CONFIG_DIR="${APPDIR}/etc/reader.conf.d"
 PCSCD_RUN_DIR="/tmp/pcscd/run"
 rm -rf "${PCSCD_RUN_DIR}"
 mkdir -p "${PCSCD_RUN_DIR}"
-echo "starting pcscd with ${APPDIR}/usr/bin/pcscd -f &"
+echo "starting pcscd with ${APPDIR}/usr/bin/pcscd --foreground --auto-exit &"
 "${APPDIR}/usr/bin/pcscd" -f &
 
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