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/layout/Stack.ts

@@ -8,9 +8,8 @@ export interface StackOptions {
 }
 
 /**
- * Lays out child widgets in a row or column. Children with `flex > 0` share the space
- * left over after fixed children got their measured size (weighted by `flex`).
- * Non-widget children are ignored by the layout but still rendered.
+ * Lays out child widgets in a row or column. Children with `flex > 0` share, weighted, the space
+ * left after the fixed ones took their measured size. Non-widget children are still rendered.
  */
 export abstract class Stack extends Widget {
   gap: number;
@@ -27,12 +26,12 @@ export abstract class Stack extends Widget {
     this.align = options.align ?? 'stretch';
   }
 
-  /** The children the layout distributes space among: visible widgets, in child order. */
+  /** The children space is distributed among: visible widgets, in child order. */
   get items(): Widget[] {
     return this.children.filter((c): c is Widget => c instanceof Widget && c.visible);
   }
 
-  /** Appends `widget` with the given flex share. Does not lay out; call `relayout()` once the stack is sized. */
+  /** Does not lay out; call `relayout()` once the stack is sized. */
   add<T extends Widget>(widget: T, flex = 0): T {
     widget.flex = flex;
     this.addChild(widget);
@@ -96,14 +95,12 @@ export abstract class Stack extends Widget {
   }
 }
 
-/** Column layout. */
 export class VStack extends Stack {
   constructor(options: StackOptions = {}) {
     super('y', options);
   }
 }
 
-/** Row layout. */
 export class HStack extends Stack {
   constructor(options: StackOptions = {}) {
     super('x', options);