test(android): RenderingControl lower clamp + GetVolume request body checks

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

android/app/src/test/java/com/fabledsword/minstrel/player/output/upnp/RenderingControlClientTest.kt

@@ -37,6 +37,13 @@ class RenderingControlClientTest {
                  </s:Body>
                </s:Envelope>""".trimIndent()))
         assertEquals(42, client.getVolume())
+        val request = server.takeRequest()
+        val body = request.body.readUtf8()
+        assertTrue(body.contains("<Channel>Master</Channel>")) { body }
+        assertEquals(
+            "\"urn:schemas-upnp-org:service:RenderingControl:1#GetVolume\"",
+            request.getHeader("SOAPACTION"),
+        )
     }
 
     @Test
@@ -53,4 +60,19 @@ class RenderingControlClientTest {
         val body = server.takeRequest().body.readUtf8()
         assertTrue(body.contains("<DesiredVolume>100</DesiredVolume>")) { body }
     }
+
+    @Test
+    fun `setVolume clamps below VOLUME_MIN to zero`() = runTest {
+        server.enqueue(MockResponse().setBody(
+            """<?xml version="1.0"?>
+               <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
+                 <s:Body>
+                   <u:SetVolumeResponse
+                       xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1"/>
+                 </s:Body>
+               </s:Envelope>""".trimIndent()))
+        client.setVolume(-5)
+        val body = server.takeRequest().body.readUtf8()
+        assertTrue(body.contains("<DesiredVolume>0</DesiredVolume>")) { body }
+    }
 }