Fix broadcast broken: reconnect loop, listener stuck on waiting

- server.py: Increase ping_timeout 10->60, ping_interval 5->25 to prevent
  frequent socket disconnects during audio streaming
- server.py: Guard dj_start() against reconnect loops - only clear pre-roll
  and emit broadcast_started on a fresh broadcast, not on DJ reconnects
- listener.js: Add polling fallback to transports (websocket-only caused
  silent failure on upgrade error), set reconnectionAttempts to Infinity
- script.js: Same transport fallback fix for DJ panel socket
- techdj_qt.py: Add _broadcast_started flag to StreamingWorker.on_connect
  so streaming_started signal only fires once; reconnects resume silently.
  Reset flag in stop_streaming() for clean next session.

listener.js

@@ -93,9 +93,11 @@ function initSocket() {
     console.log(`[LISTENER] Initializing Socket.IO connection to: ${serverUrl}`);
 
     socket = io(serverUrl, {
-        transports: ['websocket'],
+        transports: ['websocket', 'polling'],
         reconnection: true,
-        reconnectionAttempts: 10
+        reconnectionAttempts: Infinity,
+        reconnectionDelay: 1000,
+        reconnectionDelayMax: 10000
     });
 
     socket.on('connect', () => {

script.js

@@ -1844,9 +1844,11 @@ function initSocket() {
     console.log(`   Host: ${window.location.host}`);
 
     socket = io(serverUrl, {
-        transports: ['websocket'],
+        transports: ['websocket', 'polling'],
         reconnection: true,
-        reconnectionAttempts: 10
+        reconnectionAttempts: Infinity,
+        reconnectionDelay: 1000,
+        reconnectionDelayMax: 10000
     });
 
     socket.on('connect', () => {

server.py

@@ -586,8 +586,8 @@ dj_socketio = SocketIO(
     cors_allowed_origins=CONFIG_CORS, 
     async_mode='eventlet',
     max_http_buffer_size=CONFIG_MAX_UPLOAD_MB * 1024 * 1024,
-    ping_timeout=10, 
-    ping_interval=5,
+    ping_timeout=60, 
+    ping_interval=25,
     logger=CONFIG_DEBUG,
     engineio_logger=CONFIG_DEBUG
 )
@@ -611,6 +611,7 @@ def stop_broadcast_after_timeout():
 
 @dj_socketio.on('start_broadcast')
 def dj_start(data=None):
+    was_already_active = broadcast_state.get('active', False)
     broadcast_state['active'] = True
     session['is_dj'] = True
     print("BROADCAST: ACTIVE")
@@ -625,13 +626,20 @@ def dj_start(data=None):
             is_mp3_input = True
     broadcast_state['is_mp3_input'] = is_mp3_input
 
-    # Clear pre-roll for fresh start
-    with _mp3_lock:
-        _mp3_preroll.clear()
-    
-    _start_transcoder_if_needed(is_mp3_input=is_mp3_input)
-    
-    listener_socketio.emit('broadcast_started', namespace='/')
+    if not was_already_active:
+        # Fresh broadcast start - clear pre-roll and start transcoder cleanly
+        with _mp3_lock:
+            _mp3_preroll.clear()
+        _start_transcoder_if_needed(is_mp3_input=is_mp3_input)
+        # Tell listeners a new broadcast has begun (triggers audio player reload)
+        listener_socketio.emit('broadcast_started', namespace='/')
+    else:
+        # DJ reconnected mid-broadcast - just ensure transcoder is alive
+        # Do NOT clear pre-roll or trigger listener reload
+        print("BROADCAST: DJ reconnected - resuming existing broadcast")
+        _start_transcoder_if_needed(is_mp3_input=is_mp3_input)
+
+    # Always send current status so any waiting listeners get unblocked
     listener_socketio.emit('stream_status', {'active': True}, namespace='/')
 
 @dj_socketio.on('get_listener_count')
@@ -687,8 +695,8 @@ listener_socketio = SocketIO(
     cors_allowed_origins=CONFIG_CORS, 
     async_mode='eventlet',
     max_http_buffer_size=CONFIG_MAX_UPLOAD_MB * 1024 * 1024,
-    ping_timeout=10, 
-    ping_interval=5,
+    ping_timeout=60, 
+    ping_interval=25,
     logger=CONFIG_DEBUG,
     engineio_logger=CONFIG_DEBUG
 )

techdj_qt.py

@@ -812,11 +812,18 @@ class StreamingWorker(QThread):
         self.stream_url = ""
         self.is_running = False
         self.ffmpeg_proc = None
+        self._broadcast_started = False
 
     def on_connect(self):
         print("[SOCKET] Connected to DJ server")
-        self.sio.emit('start_broadcast', {'format': 'mp3', 'bitrate': '128k'})
-        self.streaming_started.emit()
+        if not self._broadcast_started:
+            self._broadcast_started = True
+            self.sio.emit('start_broadcast', {'format': 'mp3', 'bitrate': '128k'})
+            self.streaming_started.emit()
+        else:
+            # Reconnected mid-stream - server handles resume gracefully
+            print("[SOCKET] Reconnected - resuming existing broadcast")
+            self.sio.emit('start_broadcast', {'format': 'mp3', 'bitrate': '128k'})
 
     def on_disconnect(self):
         print("[SOCKET] Disconnected from DJ server")
@@ -878,6 +885,7 @@ class StreamingWorker(QThread):
 
     def stop_streaming(self):
         self.is_running = False
+        self._broadcast_started = False
         if self.ffmpeg_proc:
             try: self.ffmpeg_proc.terminate()
             except: pass