Dedupe MSDP vitals to avoid spamming idle clients

Cache last-sent values on Player and skip send_msdp() when
nothing changed. Idle players no longer get a packet every second.

src/mudlib/gmcp.py

@@ -115,14 +115,19 @@ def send_map_data(player: Player) -> None:
 
 
 def send_msdp_vitals(player: Player) -> None:
-    """Send MSDP variable updates for real-time gauges."""
+    """Send MSDP variable updates for real-time gauges.
+
+    Skips sending if values haven't changed since last send.
+    """
     if not player.msdp_enabled:
         return
-    player.send_msdp(
-        {
+    data = {
         "HEALTH": str(round(player.pl, 1)),
         "HEALTH_MAX": str(round(player.max_pl, 1)),
         "STAMINA": str(round(player.stamina, 1)),
         "STAMINA_MAX": str(round(player.max_stamina, 1)),
     }
-    )
+    if data == player._last_msdp:
+        return
+    player._last_msdp = data
+    player.send_msdp(data)

src/mudlib/player.py

@@ -30,6 +30,7 @@ class Player(Entity):
     paint_mode: bool = False
     painting: bool = False
     paint_brush: str = "."
+    _last_msdp: dict = field(default_factory=dict, repr=False)
 
     @property
     def mode(self) -> str:

tests/test_gmcp.py

@@ -231,6 +231,21 @@ def test_send_msdp_vitals(player):
     )
 
 
+def test_send_msdp_vitals_dedup(player):
+    """Test MSDP skips sending when values haven't changed."""
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 1
+
+    # second call with same values — should be suppressed
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 1
+
+    # change a value — should send again
+    player.pl = 80.0
+    send_msdp_vitals(player)
+    assert player.writer.send_msdp.call_count == 2
+
+
 def test_player_send_gmcp(player):
     """Test Player.send_gmcp convenience method."""
     player.send_gmcp("Test.Package", {"key": "value"})