fix: action message routing and duplicate local echo in geohash channels (#374)

* fix: send action messages to correct chat

* fix(action): avoid double local echo for action messages in geohash channels

When sending /hug or /slap in a location (geohash) channel, CommandProcessor
was adding a local echo and then routing to NostrGeohashService, which also
adds a local echo. This resulted in duplicate action messages on the sender’s
screen.

Change: detect when the selectedLocationChannel is a Location and, in that
case, skip adding the local echo in CommandProcessor and only call the
onSendMessage transport callback (NostrGeohashService will add the echo with
proper metadata). Private and mesh (non-location) behavior is unchanged.

app/src/main/java/com/bitchat/android/ui/ChatViewModel.kt

@@ -266,9 +266,21 @@ class ChatViewModel(
         
         // Check for commands
         if (content.startsWith("/")) {
+            val selectedLocationForCommand = state.selectedLocationChannel.value
             commandProcessor.processCommand(content, meshService, meshService.myPeerID, { messageContent, mentions, channel ->
-                meshService.sendMessage(messageContent, mentions, channel)
-            }, this)
+                if (selectedLocationForCommand is com.bitchat.android.geohash.ChannelID.Location) {
+                    // Route command-generated public messages via Nostr in geohash channels
+                    nostrGeohashService.sendGeohashMessage(
+                        messageContent,
+                        selectedLocationForCommand.channel,
+                        meshService.myPeerID,
+                        state.getNicknameValue()
+                    )
+                } else {
+                    // Default: route via mesh
+                    meshService.sendMessage(messageContent, mentions, channel)
+                }
+            })
             return
         }