Overhaul: 5-task implementation

- Remove TURN decks (3/4), clean up MIDI, layout
- Single cart player with 3-item autoload queue + continue toggle
- Event logging (SessionLogger), mic tracking, large mic timer widget
- LUFS metering moved from external ports to internal master mix
- Master output WAV recording with top-bar REC toggle
- Music mix output (ch 3-8 only, no mics)
- Preview bar for playlist auditioning
- Merged show log with [SONG][CART][TALK] prefixes
- Live CSV writer for OBS song display (~/live_songs.csv)
- Misc fixes: preview race condition, datetime import for recording

top_bar_widget.py

@@ -47,6 +47,7 @@ class TopBarWidget(QFrame):
     ratio_changed = Signal(int, int)
     save_session = Signal()
     load_session = Signal()
+    recording_toggled = Signal(bool)
 
     def __init__(self, parent=None):
         super().__init__(parent)
@@ -98,6 +99,32 @@ class TopBarWidget(QFrame):
         self.station_label.setStyleSheet("color: #555555; background: transparent; border: none;")
         layout.addWidget(self.station_label)
 
+        layout.addStretch()
+
+        self.record_btn = QPushButton("● REC")
+        self.record_btn.setCheckable(True)
+        self.record_btn.setFixedSize(70, 30)
+        self.record_btn.setFont(QFont("Arial", 8, QFont.Bold))
+        self.record_btn.setToolTip("Record master output to WAV")
+        self.record_btn.setStyleSheet("""
+            QPushButton {
+                background-color: #2a1a1a;
+                color: #664444;
+                border: 1px solid #442222;
+                border-radius: 3px;
+                padding: 0 6px;
+            }
+            QPushButton:checked {
+                background-color: #4a1a1a;
+                color: #ff4444;
+                border: 1px solid #ff4444;
+            }
+            QPushButton:hover { color: #ff8888; }
+            QPushButton:checked:hover { background-color: #5a2020; }
+        """)
+        self.record_btn.toggled.connect(self._on_record_toggled)
+        layout.addWidget(self.record_btn)
+
         self.settings_btn = QPushButton()
         self.settings_btn.setFixedSize(24, 24)
         self.settings_btn.setIconSize(QSize(14, 14))
@@ -132,6 +159,9 @@ class TopBarWidget(QFrame):
 
     # ── Settings popup ─────────────────────────────────────────────
 
+    def _on_record_toggled(self, checked):
+        self.recording_toggled.emit(checked)
+
     def _toggle_settings_popup(self):
         self._popup = SettingsPopup(self._midi_engine, self)
         self._popup.save_session.connect(self.save_session.emit)
@@ -346,12 +376,7 @@ class SettingsPopup(QFrame):
             ("Deck 1 Cue",        "deck_cue",        "deck1"),
             ("Deck 2 Play/Pause", "deck_play_pause", "deck2"),
             ("Deck 2 Cue",        "deck_cue",        "deck2"),
-            ("Deck 3 Play/Pause", "deck_play_pause", "deck3"),
-            ("Deck 4 Play/Pause", "deck_play_pause", "deck4"),
-            ("Cart 1",            "cart_trigger",    0),
-            ("Cart 2",            "cart_trigger",    1),
-            ("Cart 3",            "cart_trigger",    2),
-            ("Cart 4",            "cart_trigger",    3),
+            ("Cart Trigger",      "cart_trigger",    0),
             ("Ch 1 Volume",       "mixer_volume",    0),
             ("Ch 2 Volume",       "mixer_volume",    1),
             ("Ch 3 Volume",       "mixer_volume",    2),