diag(android): log raw SOAP response body for first 3 UPnP polls

Add optional onRawResponse callback to SoapClient; loggingSoapClient
factory emits the first 6 GetPositionInfo/GetTransportInfo bodies
(3 poll cycles) at WARN so release logs capture them. Wire into
transportFor so every AVTransportClient for a new UPnP session logs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/SoapClient.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel.player.output.upnp
 
+import java.util.concurrent.atomic.AtomicInteger
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import okhttp3.HttpUrl
@@ -8,6 +9,7 @@ import okhttp3.Request
 import okhttp3.RequestBody.Companion.toRequestBody
 import org.xmlpull.v1.XmlPullParser
 import org.xmlpull.v1.XmlPullParserFactory
+import timber.log.Timber
 
 /**
  * Minimal SOAP/UPnP envelope builder + POST. Hand-rolled rather than
@@ -25,6 +27,7 @@ import org.xmlpull.v1.XmlPullParserFactory
  */
 class SoapClient(
     private val okHttp: OkHttpClient,
+    private val onRawResponse: ((action: String, body: String) -> Unit)? = null,
 ) {
     suspend fun call(
         controlUrl: HttpUrl,
@@ -41,6 +44,7 @@ class SoapClient(
             .build()
         okHttp.newCall(request).execute().use { response ->
             val body = response.body?.string().orEmpty()
+            onRawResponse?.invoke(action, body)
             if (!response.isSuccessful) {
                 throw SoapFaultException(faultCodeOf(body), faultDescriptionOf(body))
             }
@@ -132,6 +136,28 @@ class SoapClient(
 class SoapFaultException(val code: String, val description: String) :
     Exception("SOAP fault $code: $description")
 
+private const val MAX_DIAGNOSTIC_RESPONSES = 6  // 3 polls x 2 action types
+private const val MAX_BODY_LOG_CHARS = 2048
+
+/**
+ * Returns a [SoapClient] that logs the raw response body for the first
+ * [MAX_DIAGNOSTIC_RESPONSES] GetPositionInfo / GetTransportInfo calls (i.e.
+ * the first 3 poll cycles of a UPnP session). After that the callback is a
+ * no-op so there is no persistent log spam. Logged at WARN so release builds
+ * capture it without a separate log-level override.
+ */
+internal fun loggingSoapClient(okHttp: OkHttpClient, label: String): SoapClient {
+    val counter = AtomicInteger(0)
+    return SoapClient(okHttp) { action, body ->
+        if (action != "GetPositionInfo" && action != "GetTransportInfo") return@SoapClient
+        val n = counter.incrementAndGet()
+        if (n <= MAX_DIAGNOSTIC_RESPONSES) {
+            Timber.w("UPnP %s response #%d (%s): %s",
+                label, n, action, body.take(MAX_BODY_LOG_CHARS))
+        }
+    }
+}
+
 /** XML-escapes a string value for embedding as text content inside a SOAP envelope. */
 internal fun xmlEscape(v: String): String = v
     .replace("&", "&amp;")

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/UpnpDiscoveryController.kt

@@ -90,7 +90,7 @@ class UpnpDiscoveryController @Inject constructor(
      */
     fun transportFor(routeId: String): AVTransportClient? {
         val route = routesInternal.value.firstOrNull { it.id == routeId } ?: return null
-        return AVTransportClient(SoapClient(okHttp), route.avTransportControlUrl)
+        return AVTransportClient(loggingSoapClient(okHttp, route.name), route.avTransportControlUrl)
     }
 
     private suspend fun handleDiscovery(locationUrl: String) {