Trim needless comments and fix the picker width

Remove comments that only restate the code, keeping the section banners
and the notes that carry a reason, a measured fact or an external
contract.

ButtonOptions.width claimed to be a fixed width but only set minWidth,
so the Graph and Texture pickers grew with the name they showed. It is
now what it promises, with a separate minWidth for the buttons that have
two forms. Narrow buttons shrink their padding, otherwise a 24px icon
button had 8px left for its glyph and truncate dropped it entirely.

__gm.labelsDropped() guards that class: the overflow guard only saw text
that was too wide, never a label truncated to nothing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/panels/AssetPanel.ts

@@ -73,7 +73,7 @@ export class AssetPanel extends Panel {
 
   /**
    * A texture is an uploaded picture, so its menu entry opens the file dialog instead of
-   * creating an empty asset – a texture without an image would draw nothing.
+   * creating an empty asset.
    */
   private importTextures(): void {
     if (!this.textures) {