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>

tools/e2e/13-frames.mjs

@@ -1,13 +1,10 @@
 /**
  * The Texture tab: cutting frames out of a sheet, and a sprite wearing one.
  *
- * Runs after the texture step, whose four-quadrant 64x48 picture is what makes this checkable
- * at all – a frame over one quadrant has a colour of its own, so "which part of the sheet is
- * on screen" is a question `pixelAt` can answer. Nothing here is stubbed: the frame is made by
- * dragging on the canvas, and the sprite is read back off the rendered pixels.
+ * Runs after the texture step, whose four-quadrant 64x48 picture gives every quadrant a colour
+ * of its own – that is what makes "which part of the sheet is on screen" a `pixelAt` question.
  */
 
-/** How far apart two `#rrggbb` colours are, summed over the channels. */
 function colourDistance(a, b) {
   const channels = (hex) => [1, 3, 5].map((i) => parseInt(hex.slice(i, i + 2), 16));
   const [ar, ag, ab] = channels(a);
@@ -21,21 +18,12 @@ const PALETTE = {
   green: '#3cc85a',
   blue: '#466ef0',
   white: '#f5f5f5',
-  /**
-   * The sprite's own colour for the fallback check, deliberately a colour the sheet does not
-   * contain. The sheet's fourth quadrant is near-white, so leaving the sprite white would make
-   * "it fell back to its colour" and "it is showing that quadrant" the same measurement.
-   */
   plain: '#ff00ff',
 };
 
 /**
- * Which of the known colours a sampled pixel is: the nearest one by channel distance.
- *
- * Asked this way rather than "is it exactly green" on purpose. The scene carries editor gizmos
- * by this point – a collider's fill is drawn over its body at 12 % alpha – so a sample can be
- * tinted by a few percent without anything being wrong. That shifts a colour slightly; it
- * cannot make one quadrant of the sheet read as another, which is the only question here.
+ * Nearest known colour rather than an exact match: editor gizmos (a collider fill at 12 % alpha)
+ * tint a sample by a few percent, which still cannot make one quadrant read as another.
  */
 function nearestColour(sample) {
   let best = '';
@@ -68,9 +56,8 @@ export async function frames(t) {
   );
   await shot('33-texture-tab');
 
-  // 21. Dragging on the picture cuts a frame. The drag is aimed at the top-right quadrant of
-  //     the sheet (32,0)-(64,24), inset by a pixel so the press cannot land on the edge of a
-  //     neighbouring frame and be read as a resize instead of a new rectangle.
+  // 21. Dragging on the picture cuts a frame. Aimed at the top-right quadrant (32,0)-(64,24),
+  //     inset by a pixel: a press on a frame edge is read as a resize, not a new rectangle.
   const from = await json('__gm.texture.pointAt(33, 1)');
   const to = await json('__gm.texture.pointAt(63, 23)');
   check('the sheet is on screen', Boolean(from) && Boolean(to), JSON.stringify({ from, to }));
@@ -111,11 +98,7 @@ export async function frames(t) {
   await t.redo();
   await sleep(400);
 
-  // 22. A sprite wearing the frame shows that part of the sheet and nothing else. This is the
-  //     check the whole feature exists for: the model difference between "whole picture" and
-  //     "this frame" is one id, so only the drawn pixels can tell them apart.
-  //     The sprite from the texture step is reused, white and unparented, but its texture
-  //     reference was left dangling there – it is pointed at the frame here.
+  // 22. A sprite wearing the frame shows that part of the sheet and nothing else.
   await evaluate(`(() => {
     const sprite = __gm.state.project.assets.find((a) => a.id === 'tex-sprite');
     sprite.props.color = 0xffffff;
@@ -132,9 +115,8 @@ export async function frames(t) {
       json(`__gm.pixelAt(${Math.round(box.x + fx * box.w)}, ${Math.round(box.y + fy * box.h)})`);
     const corners = [await at(-0.3, -0.3), await at(0.3, -0.3), await at(-0.3, 0.3), await at(0.3, 0.3)];
     const read = corners.map(nearestColour);
-    // Without the frame these four corners read red / green / blue / white – that is what the
-    // texture step asserts one screen earlier. Reading green four times is therefore the exact
-    // statement that the fill was confined to one quadrant of the sheet.
+    // Without the frame these corners read red / green / blue / white, as the texture step
+    // asserts – so four greens is the statement that the fill stayed inside one quadrant.
     check(
       'the whole sprite shows the one quadrant the frame cuts out',
       read.every((c) => c === 'green'),
@@ -143,10 +125,9 @@ export async function frames(t) {
     await shot('35-sprite-wearing-a-frame');
   }
 
-  // 23. Slicing offers a live count before it commits – the readout is what makes the numbers
-  //     answerable without undoing.
-  // Repainted magenta before slicing: with the frame gone the sprite falls back to this, and
-  // magenta is nowhere in the sheet, so the fallback cannot be confused with a part of it.
+  // 23. Slicing offers a live count before it commits.
+  // Repainted magenta first: magenta is nowhere in the sheet, so the fallback check below
+  // cannot be confused with a part of the picture.
   await evaluate(`(() => {
     __gm.state.project.assets.find((a) => a.id === 'tex-sprite').props.color = 0xff00ff;
     __gm.state.preview();
@@ -180,8 +161,7 @@ export async function frames(t) {
   check('and numbers them in reading order', sliced[0]?.startsWith('Frame 1 '), JSON.stringify(sliced[0]));
   await shot('36-sliced-sheet');
 
-  // 23a. The sprite pointed at the frame that slicing removed falls back to its colour rather
-  //      than to a wrong part of the picture.
+  // 23a. A sprite pointed at a frame slicing removed falls back to its colour.
   await evaluate("__gm.showTab('scene')");
   await sleep(700);
   if (box) {