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/ui/widgets/Label.ts

@@ -6,7 +6,6 @@ import { type Size, Widget } from '../Widget';
 export interface LabelOptions {
   style?: TextStyleToken;
   align?: 'left' | 'center' | 'right';
-  /** Horizontal padding inside the label bounds. */
   padding?: number;
 }