Add Volume control and OpenUri support

- Implement MPRIS Volume property (readwrite) with 0-10 mapping for Winamp
- Implement MPRIS OpenUri method using the discovered /url?p& endpoint
- Add Volume to PropertiesChanged signal notifications
- Update D-Bus XML interface definition

winamp_mpris.py

@@ -70,7 +70,9 @@ class WinampMPRIS:
         <property name="Position" type="x" access="read">
             <annotation name="org.freedesktop.DBus.Property.EmitsChangedSignal" value="false"/>
         </property>
-        <property name="Volume" type="d" access="read" />
+        <property name="Volume" type="d" access="readwrite">
+            <annotation name="org.freedesktop.DBus.Property.EmitsChangedSignal" value="true"/>
+        </property>
       </interface>
     </node>
     """
@@ -89,6 +91,7 @@ class WinampMPRIS:
         self._last_update_ts = time.time()
         self._shuffle = False
         self._loop_status = "None"
+        self._volume = 1.0
 
     def _request(self, endpoint):
         print(f"COMMAND RECEIVED: {endpoint}")
@@ -112,7 +115,9 @@ class WinampMPRIS:
     def Stop(self): self._request("stop")
     def Seek(self, offset): pass
     def SetPosition(self, track_id, position): pass
-    def OpenUri(self, uri): pass
+    def OpenUri(self, uri):
+        # Found /url?p&<url> in source code - plays immediately
+        self._request(f"url?p&{uri}")
 
     # --- Root Properties ---
     @property
@@ -185,7 +190,13 @@ class WinampMPRIS:
         return self._last_position_us
 
     @property
-    def Volume(self): return 1.0
+    def Volume(self): return self._volume
+    @Volume.setter
+    def Volume(self, value):
+        self._volume = max(0.0, min(1.0, value))
+        # Plugin source shows /vol?volume= accepts 0-10
+        vol_10 = int(self._volume * 10)
+        self._request(f"vol?volume={vol_10}")
 
     @property
     def Metadata(self):
@@ -380,7 +391,8 @@ def update_loop(player):
                         "PlaybackStatus": player.PlaybackStatus,
                         "Metadata": player.Metadata,
                         "Shuffle": player.Shuffle,
-                        "LoopStatus": player.LoopStatus
+                        "LoopStatus": player.LoopStatus,
+                        "Volume": player.Volume
                     },
                     []
                 )