feat: Add digital, dry, ink, and paint brush presets; implement regression testing hooks

- Introduced new crates for digital brushes, dry media brushes, ink brushes, and paint brushes, each containing various presets.
- Updated the menus to include "Paste Special" and "Paste as New Layer" options.
- Enhanced the feature scorecard tests to validate selection texture encoding.
- Added a regression gate workflow for automated testing on push and pull requests.
- Implemented Git hooks for pre-commit checks to ensure code formatting and run tests before commits.
- Created a settings file for local configurations.

hcie-brush-engine/examples/brush_test.rs

@@ -581,6 +581,13 @@ impl eframe::App for App {
                             self.preset.tip.color_variant,
                             self.preset.tip.variant_amount,
                             self.preset.tip.density,
+                            self.preset.tip.jitter_amount,
+                            self.preset.tip.scatter_amount,
+                            self.preset.tip.angle,
+                            self.preset.tip.roundness,
+                            self.preset.tip.rotation_random,
+                            self.preset.tip.drawing_angle,
+                            true,
                         );
                         self.stroke_count += 1;