fix: Remove redundant Settings plugin and baked-in Spotify widget

CHANGES:
1. Settings plugin is no longer categorized as 'Core' plugin
   - The settings menu is built into the overlay window
   - Having both was redundant
   - Settings plugin still exists but won't be auto-enabled

2. Removed hardcoded SpotifyWidget from core/dashboard.py
   - Spotify widget was baked into core instead of being a proper plugin
   - Should be in plugins/spotify_controller/ instead
   - Commented out the widget addition for now

This addresses the user's feedback that:
- Settings plugin is redundant with the settings menu
- Spotify widget shouldn't be in core

core/dashboard.py

@@ -382,8 +382,8 @@ class Dashboard(QWidget):
         ]
         self.add_widget(QuickActionsWidget(actions))
         
-        # Spotify widget (if available)
-        self.add_widget(SpotifyWidget())
+        # Spotify widget removed - should be in plugins/spotify_controller instead
+        # self.add_widget(SpotifyWidget())
         
         # PED tracker
         self.add_widget(PEDTrackerWidget())

core/overlay_window.py

@@ -849,7 +849,7 @@ class OverlayWindow(QMainWindow):
                                                 'plugins.mining_helper', 'plugins.chat_logger',
                                                 'plugins.global_tracker', 'plugins.nexus_search',
                                                 'plugins.universal_search', 'plugins.calculator',
-                                                'plugins.settings', 'plugins.dashboard')):
+                                                'plugins.dashboard')) and 'settings' not in plugin_id:
                         core_plugins.append((plugin_id, plugin_class))
                     else:
                         other_plugins.append((plugin_id, plugin_class))