android: fix PTT — one Box across all states, release now works; 1s min duration

- PTT Box: same composable identity in idle/recording states (just changes bg color)
  Gesture coroutine survives recomposition → onPttReleased() fires on finger lift.
  When locked, Box is replaced by cancel/send IconButtons.
- Min voice duration: 500→1000ms (C and ViewModel)

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/components/MessageBubble.kt

@@ -167,27 +167,20 @@ fun InputBar(
         Spacer(Modifier.width(4.dp))
 
         if (isRecording && isRecordingLocked) {
-            /* Locked: cancel + send voice */
+            /* Locked: cancel + send voice — PTT box replaced by action buttons */
             IconButton(onClick = onVoiceCancel) {
                 Text("\u2715", fontSize = 20.sp, color = Color(0xFFE53935))
             }
             IconButton(onClick = onVoiceSend) {
                 Text("\u25B6", fontSize = 20.sp, color = Color(0xFF4CAF50))
             }
-        } else if (isRecording) {
-            /* Holding: only PTT active */
-            IconButton(
-                onClick = {},
-                enabled = true,
-                modifier = Modifier.background(Color(0xFFE53935), RoundedCornerShape(4.dp))
-            ) {
-                Text("\uD83C\uDFA4", fontSize = 20.sp)
-            }
         } else {
-            /* Idle: PTT + send */
+            /* PTT Box — always present (same identity), just changes appearance */
+            val pttBg = if (isRecording) Color(0xFFE53935) else Color.Transparent
             Box(
                 modifier = Modifier
                     .size(48.dp)
+                    .background(pttBg, RoundedCornerShape(4.dp))
                     .pointerInput(hasMicPerm) {
                         awaitPointerEventScope {
                             val down = awaitPointerEvent()
@@ -223,13 +216,14 @@ fun InputBar(
                     },
                 contentAlignment = Alignment.Center
             ) {
-                Text("\uD83C\uDFA4", fontSize = 20.sp)
+                Text("\uD83C\uDFA4", fontSize = 20.sp, color = if (isRecording) Color.White else Color.Unspecified)
             }
 
-            Spacer(Modifier.width(4.dp))
-
-            Button(onClick = onSend, enabled = enabled && text.isNotBlank()) {
-                Text("Send")
+            if (!isRecording) {
+                Spacer(Modifier.width(4.dp))
+                Button(onClick = onSend, enabled = enabled && text.isNotBlank()) {
+                    Text("Send")
+                }
             }
         }
     }

tools/chatgui-android/app/src/main/java/com/utun/chat/viewmodel/ChatViewModel.kt

@@ -239,7 +239,7 @@ class ChatViewModel : ViewModel() {
 
     fun sendVoiceMessage() {
         val duration = stopVoiceRecording()
-        if (duration < 500) {
+        if (duration < 1000) {
             LogManager.addLog("INFO", "VM", "voice too short (${duration}ms), discarded")
         }
     }

tools/chatgui-android/libutun_lite/voice_recorder.c

@@ -221,7 +221,7 @@ int voice_recorder_stop(int* out_duration_ms) {
         return -1;
     }
 
-    if (elapsed_ms < 500) {
+    if (elapsed_ms < 1000) {
         DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "voice_recorder_stop: too short %lldms, discarding", (long long)elapsed_ms);
         voice_cleanup_locked(g_rec);
         pthread_mutex_unlock(&g_rec->mtx);