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/App.ts

@@ -10,8 +10,8 @@ import { EditorState } from './state';
 const API_ENDPOINT = '/game-maker/api/index.php';
 
 /**
- * Where uploaded images live. The API writes them; the browser reads them straight off disk,
- * with no PHP in the path – they are static files whose names are their content hashes.
+ * Where uploaded images live: the API writes them, the browser reads them straight off disk as
+ * static files named by their content hash.
  */
 const TEXTURE_BASE = '/game-maker/data/textures';