GOOD Refactor GUI components and add PlainSlider widget

- Added a new `PlainSlider` widget for keyboard-editable numeric sliders.
- Updated various panels to utilize the new `PlainSlider` for better user interaction.
- Removed unused code and dead code warnings across multiple files.
- Improved organization of modules by adding a `widgets` module.
- Cleaned up imports in several files to streamline the codebase.
- Added Qodana configuration file for code analysis and quality checks.

hcie-engine-api/src/lib.rs

@@ -1530,9 +1530,11 @@ impl Engine {
     }
 
     /// Get mutable reference to shapes on a vector layer for direct manipulation.
+    /// Marks the layer dirty so the composite is regenerated on the next render pass.
     pub fn get_layer_shapes_direct(&mut self, layer_id: u64) -> Option<&mut Vec<VectorShape>> {
         if let Some(layer) = self.document.get_layer_by_id_mut(layer_id) {
             if let LayerData::Vector { ref mut shapes } = layer.data {
+                layer.dirty = true;
                 return Some(shapes);
             }
         }