Fix NuForce uDAC USB disconnects

Cheap Savitech chip firmware stalls on rapid SET_INTERFACE / sample-rate
renegotiation, eventually dropping off the USB bus and requiring a
physical replug. Two fixes, both scoped to this exact device only:

- snd_usb_audio quirk_flags (262a:10aa): fixed_rate + ctl_msg_delay +
  iface_delay, applied via /etc/modprobe.d during bootstrap.
- WirePlumber: disable idle-suspend for the device's ALSA node so
  PipeWire doesn't repeatedly reopen the stream during normal use.

.config/wireplumber/wireplumber.conf.d/51-nuforce-no-suspend.conf

@@ -0,0 +1,23 @@
+# The NuForce uDAC (Savitech chip) has flaky firmware: when PipeWire
+# idles and then resumes its ALSA node, the device often fails the
+# resulting SET_INTERFACE / sample-rate renegotiation with a USB stall
+# (spa.alsa: set_hw_params: Broken pipe). Enough of these in a row make
+# the device drop off the USB bus and require a physical replug.
+#
+# Keeping the node's hardware stream open (no idle-suspend) avoids the
+# repeated renegotiation and stops the crashes.
+
+monitor.alsa.rules = [
+  {
+    matches = [
+      {
+        node.name = "~alsa_output.usb-Nuforce_Inc\\._NuForce_USB_Audio-.*"
+      }
+    ]
+    actions = {
+      update-props = {
+        session.suspend-timeout-seconds = 0
+      }
+    }
+  }
+]