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/editor/ProjectSession.ts

@@ -1,6 +1,5 @@
 /**
- * Loading, creating, switching and deleting projects, plus the two toolbar menus that trigger
- * it. Talks only to the store and the editor state – no widgets of its own beyond the menus.
+ * Loading, creating, switching and deleting projects, plus the two toolbar menus that trigger it.
  */
 import { SetActiveSceneCommand } from '../core/commands/assetCommands';
 import { listScenes } from '../core/model/Project';
@@ -10,8 +9,8 @@ import type { EditorState } from './state';
 
 export class ProjectSession {
   /**
-   * `beforeSwitch` runs before a different project is loaded or the current one is deleted –
-   * a run in progress has to end first, since it holds a copy of the project being replaced.
+   * `beforeSwitch` runs before a different project is loaded or the current one is deleted: a
+   * run in progress holds a copy of the project being replaced and has to end first.
    */
   constructor(
     private readonly state: EditorState,