chore: temporary diagnostic logging for public chat relay targeting

Logs the relay set targeted by the public-chat send path and the broadcast
path under tag "PublicChatRelayDebug", so an on-device repro can show whether
the channel-declared relay is actually in the target set. To be reverted once
the declared-relay case is diagnosed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AYtHYEob2THu74inTxZxCh

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -1403,7 +1403,13 @@ class Account(
                 // missing signature.
                 return
             } else {
-                client.publish(noteEvent, computeRelayListToBroadcast(note))
+                val toRelays = computeRelayListToBroadcast(note)
+                // TEMP DIAGNOSTIC (public chat relay bug): what does broadcast target?
+                Log.w("PublicChatRelayDebug") {
+                    "BROADCAST event=${noteEvent.id} kind=${noteEvent.kind} " +
+                        "channelRelays=${cache.getAnyChannel(noteEvent)?.relays()} -> target=$toRelays"
+                }
+                client.publish(noteEvent, toRelays)
             }
         }
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/send/ChannelNewMessageViewModel.kt

@@ -301,6 +301,12 @@ open class ChannelNewMessageViewModel :
         val template = createTemplate() ?: return
         val channelRelays = channel?.relays() ?: emptySet()
 
+        // TEMP DIAGNOSTIC (public chat relay bug): what relays does the send target?
+        val pubChat = channel as? PublicChatChannel
+        Log.w("PublicChatRelayDebug") {
+            "SEND channel=${pubChat?.idHex} declared(info.relays)=${pubChat?.info?.relays} -> target=$channelRelays (empty target -> broadcast fallback)"
+        }
+
         val version = draftTag.current
         cancel()