A GOOD MILESTONE : Refactor title bar and toolbar typography, improve tooltip styles, and enhance selection transform functionality

- Updated typography constants for menu bar and tooltips to improve readability and consistency.
- Adjusted button padding and widths in the title bar for better layout.
- Replaced tooltip implementation with a new balloon tooltip style for improved visual feedback.
- Enhanced selection transform logic to support rotation and resizing, ensuring accurate hit testing and bounds calculations.
- Added tests for selection clearing and transformed bounds to ensure functionality and prevent regressions.
- Introduced a new module for managing selection transform dirty bounds during interactive previews.

hcie-document/src/lib.rs

@@ -88,7 +88,7 @@ impl Document {
     }
 
     pub fn delete_layer(&mut self, idx: usize) {
-        if self.layers.len() <= 1 || idx >= self.layers.len() { return; }
+        if idx >= self.layers.len() { return; }
 
         let layer = &self.layers[idx];
         let action = LayerDeleteAction {