perf: take per-message logging off the chat path

Every channel message wrote a fully interpolated INFO line, duplicating
what the dedicated async ChannelMessageLogger already persists. Every
cross-server message produced one INFO on the sending Paper server, two on
Velocity, and one on each receiving Paper server - so a single global chat
message cost up to four synchronous console and latest.log writes across
the network, on the message path, with JUL and Logback appenders being
synchronous.

These are now debug, and phrased so the string is not built unless debug
is on: the JUL sites take a supplier, the slf4j sites take a format plus
arguments.

Handshake, registration and delivery-failure lines stay at info - they
fire once per server or once per failed message, and they explain
something an operator needs to see.

Two relay tests asserted on the text of a log line. One of them was
verifying "0 servers" where the same test already verifies zero sends;
the other was really checking that the payload reaches the target, so it
now decodes the relayed bytes and compares them to the original message.

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

4 files changed, 27 insertions, 20 deletions

diff --git a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelay.kt b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelay.kt
index f47db70..bebc7b9 100644
--- a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelay.kt
+++ b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelay.kt
@@ -43,9 +43,12 @@ class CrossServerChatRelay(
                     relayCount++
                 }
 
-            logger.info(
-                "Relayed global chat message from ${message.serverName} to $relayCount servers " +
-                    "(messageId=${message.messageId}, player=${message.playerName})",
+            logger.debug(
+                "Relayed global chat message from {} to {} servers (messageId={}, player={})",
+                message.serverName,
+                relayCount,
+                message.messageId,
+                message.playerName,
             )
         } catch (e: Exception) {
             logger.error("Failed to relay global chat message: ${e.message}", e)
diff --git a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerDirectMessageRelay.kt b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerDirectMessageRelay.kt
index 3746395..f9cc52d 100644
--- a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerDirectMessageRelay.kt
+++ b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerDirectMessageRelay.kt
@@ -62,9 +62,13 @@ class CrossServerDirectMessageRelay(
             }
 
             targetServer.sendPluginMessage(CHANNEL, PluginMessageCodec.encode(message))
-            logger.info(
-                "Relayed direct message from ${message.senderName}@${message.sourceServerName} " +
-                    "to ${message.targetName}@${message.targetServerName} (messageId=${message.messageId})",
+            logger.debug(
+                "Relayed direct message from {}@{} to {}@{} (messageId={})",
+                message.senderName,
+                message.sourceServerName,
+                message.targetName,
+                message.targetServerName,
+                message.messageId,
             )
         } catch (e: Exception) {
             logger.error("Failed to relay direct message: ${e.message}", e)
diff --git a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/PluginMessageHandler.kt b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/PluginMessageHandler.kt
index 6b40a7e..aa0cc07 100644
--- a/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/PluginMessageHandler.kt
+++ b/platform-velocity/src/main/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/PluginMessageHandler.kt
@@ -170,9 +170,11 @@ class PluginMessageHandler(
         connection: ServerConnection,
         message: PluginMessage.GlobalChatMessage,
     ) {
-        logger.info(
-            "Received global chat message from ${connection.serverInfo.name}: " +
-                "messageId=${message.messageId}, player=${message.playerName}",
+        logger.debug(
+            "Received global chat message from {}: messageId={}, player={}",
+            connection.serverInfo.name,
+            message.messageId,
+            message.playerName,
         )
 
         crossServerChatRelay.relayGlobalMessage(message, connection.server)
diff --git a/platform-velocity/src/test/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelayTest.kt b/platform-velocity/src/test/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelayTest.kt
index 50b0db2..1cd5fbf 100644
--- a/platform-velocity/src/test/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelayTest.kt
+++ b/platform-velocity/src/test/kotlin/dev/m1sk9/lunaticChat/velocity/messaging/CrossServerChatRelayTest.kt
@@ -4,11 +4,14 @@ import com.velocitypowered.api.proxy.ProxyServer
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier
 import com.velocitypowered.api.proxy.server.RegisteredServer
 import dev.m1sk9.lunaticChat.engine.protocol.PluginMessage
+import dev.m1sk9.lunaticChat.engine.protocol.PluginMessageCodec
 import io.mockk.every
 import io.mockk.mockk
+import io.mockk.slot
 import io.mockk.verify
 import org.slf4j.Logger
 import kotlin.test.Test
+import kotlin.test.assertEquals
 
 class CrossServerChatRelayTest {
     private fun createRelay(): Triple<CrossServerChatRelay, ProxyServer, Logger> {
@@ -70,7 +73,7 @@ class CrossServerChatRelayTest {
 
     @Test
     fun `relayGlobalMessage with only source server should relay to zero`() {
-        val (relay, proxyServer, logger) = createRelay()
+        val (relay, proxyServer, _) = createRelay()
         val sourceServer = createRegisteredServer("lobby")
 
         every { proxyServer.allServers } returns listOf(sourceServer)
@@ -78,27 +81,22 @@ class CrossServerChatRelayTest {
         relay.relayGlobalMessage(createTestMessage(), sourceServer)
 
         verify(exactly = 0) { sourceServer.sendPluginMessage(any<ChannelIdentifier>(), any<ByteArray>()) }
-        verify { logger.info(match { it.contains("0 servers") }) }
     }
 
     @Test
-    fun `relayGlobalMessage should log with messageId and playerName`() {
-        val (relay, proxyServer, logger) = createRelay()
+    fun `relayGlobalMessage should forward the message unchanged`() {
+        val (relay, proxyServer, _) = createRelay()
         val sourceServer = createRegisteredServer("lobby")
         val targetServer = createRegisteredServer("survival")
+        val relayed = slot<ByteArray>()
 
         every { proxyServer.allServers } returns listOf(sourceServer, targetServer)
+        every { targetServer.sendPluginMessage(any<ChannelIdentifier>(), capture(relayed)) } returns true
 
         val message = createTestMessage(messageId = "test-msg-123")
         relay.relayGlobalMessage(message, sourceServer)
 
-        verify {
-            logger.info(
-                match { msg ->
-                    msg.contains("test-msg-123") && msg.contains("TestPlayer")
-                },
-            )
-        }
+        assertEquals(message, PluginMessageCodec.decode(relayed.captured))
     }
 
     @Test