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/core/model/SceneObject.ts

@@ -1,42 +1,34 @@
 import { type Position, type PropertyBag, toPosition, type Vec2 } from './Properties';
 
 /**
- * An asset placed inside a scene. It links to the asset by id, owns a position
- * (assets have none) and may override individual asset properties. Overrides are
- * sparse: only keys the user changed are stored; everything else follows the asset.
+ * An asset placed inside a scene. Overrides are sparse: only keys the user changed are stored,
+ * everything else follows the asset.
  */
 export interface SceneObject {
   id: string;
   assetId: string;
-  /** Optional display name; falls back to the asset name when empty. */
+  /** Falls back to the asset name when empty. */
   name: string;
-  /**
-   * Position **relative to the parent** (world position when there is no parent) plus the
-   * draw order `z`, which is relative as well. See `hierarchy.ts` for world coordinates.
-   */
+  /** Relative to the parent, `z` included; see `hierarchy.ts` for world coordinates. */
   position: Position;
   /**
-   * Editor-only shift of where this object (and everything below it) is *drawn* in the scene
-   * view – never part of the game. It exists to pull objects apart that sit on top of each
-   * other, such as the title/win/lose screens of a game, without moving them for real.
+   * Editor-only shift of where this object and everything below it is drawn – never part of the
+   * game. It pulls apart objects that sit on top of each other without moving them for real.
    */
   editorOffset: Vec2;
   overrides: PropertyBag;
   /**
-   * Parent object of the same scene, empty string = top level. Children move with their
-   * parent and are removed with it. Behaviors treat their parent as the "owner" the graph
-   * acts on.
+   * Parent object of the same scene, empty string = top level. Children move with their parent and
+   * are removed with it; behaviors treat their parent as the "owner" the graph acts on.
    */
   parentId: string;
   /**
-   * For objects that belong to a placed container: the id of the template object (inside
-   * the container asset) this one was instantiated from. Empty for everything else. This is
-   * the link that lets template changes reach the instances later on.
+   * The template object inside the container asset this one was instantiated from, empty for
+   * everything else – the link that lets template changes reach the instances later on.
    */
   templateId: string;
 }
 
-/** Creates a scene object; `z` defaults to 0 when the caller only has a 2D point. */
 export function createSceneObject(
   id: string,
   assetId: string,