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/draw.ts

@@ -4,15 +4,14 @@ import { Theme } from './Theme';
 export interface ControlBoxOptions {
   fill: number;
   border: number;
-  /** Corner radius; defaults to `Theme.radius`. */
   radius?: number;
   x?: number;
   y?: number;
 }
 
 /**
- * The shared look of every control: a rounded fill with a 1 px border. The stroke is inset by
- * half a pixel so it lands on whole device pixels and stays crisp instead of blurring over two.
+ * The shared look of every control. The stroke is inset by half a pixel so it lands on whole
+ * device pixels and stays crisp instead of blurring over two.
  */
 export function drawControlBox(g: Graphics, w: number, h: number, options: ControlBoxOptions): void {
   const { fill, border, radius = Theme.radius, x = 0, y = 0 } = options;
@@ -29,14 +28,13 @@ export interface GridOptions {
   w: number;
   h: number;
   alpha: number;
-  /** Alpha of the two lines through the origin; omitted = no axes (the graph has no origin to show). */
+  /** Alpha of the two lines through the origin; omitted = no axes. */
   axisAlpha?: number;
 }
 
 /**
- * The background grid of the scene view and the graph editor. Drawn in white at a low alpha
- * rather than in a fixed colour, so it reads on whatever background the scene sets.
- * `g` is cleared by the caller, which also decides when the step is too dense to be useful.
+ * White at a low alpha rather than a fixed colour, so the grid reads on whatever background the
+ * scene sets. `g` is cleared by the caller.
  */
 export function drawGrid(g: Graphics, options: GridOptions): void {
   const { originX, originY, step, w, h, alpha, axisAlpha } = options;