fix: HUD rebuild stability and end_session compatibility

- Add end_session() as alias for stop_session() for backward compatibility
- Use delayed rebuild with QTimer.singleShot to avoid UI glitches
- Add container.show() at end of _setup_ui to ensure visibility
- Add error handling in _do_rebuild for recovery

ui/hud_overlay_clean.py

@@ -467,6 +467,9 @@ class HUDOverlay(QWidget):
         
         layout.addLayout(footer)
         
+        # Ensure container is visible
+        self.container.show()
+    
     def _get_stylesheet(self) -> str:
         """Get stylesheet based on compact mode."""
         font_size = "11px" if self.hud_config.compact_mode else "12px"
@@ -517,14 +520,28 @@ class HUDOverlay(QWidget):
     
     def _rebuild_ui(self):
         """Rebuild UI with current config."""
-        # Delete old container and recreate
+        # Hide first to avoid visual glitch
+        self.hide()
+        
+        # Delete old container
         if hasattr(self, 'container') and self.container:
             self.container.deleteLater()
             self.container = None
         
-        # Rebuild everything
+        # Small delay to ensure cleanup
+        from PyQt6.QtCore import QTimer
+        QTimer.singleShot(10, self._do_rebuild)
+    
+    def _do_rebuild(self):
+        """Actually rebuild the UI."""
+        try:
             self._setup_ui()
             self._refresh_display()
+            self.show()
+        except Exception as e:
+            logger.error(f"Error rebuilding HUD: {e}")
+            # Try to recover
+            self.show()
     
     # === Session Management ===
     
@@ -552,6 +569,10 @@ class HUDOverlay(QWidget):
         self.status_label.setText("● Live")
         self.status_label.setStyleSheet("color: #7FFF7F; font-weight: bold;")
     
+    def end_session(self) -> None:
+        """Alias for stop_session for backward compatibility."""
+        self.stop_session()
+    
     def stop_session(self) -> None:
         """Stop the current session."""
         self.session_active = False