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/commands/variableCommands.ts

@@ -5,7 +5,7 @@ import { type Removed, removeFirst, restoreAt } from '../util/list';
 import { type Command, CommandError } from './Command';
 import { requireBehavior } from './require';
 
-/** Declares a new variable on a behavior; its default value is written to `props`. */
+/** The variable's default value is written to `props` as well. */
 export class AddVariableCommand implements Command {
   readonly label: string;
   readonly def: PropertyDef;
@@ -76,10 +76,7 @@ export class RemoveVariableCommand implements Command {
   }
 }
 
-/**
- * Renames a variable everywhere: definition, default, instance overrides (in scenes and in
- * container templates) and graph nodes referring to it.
- */
+/** Renames everywhere: definition, default, instance overrides and the graph nodes referring to it. */
 export class RenameVariableCommand implements Command {
   readonly label: string;
 
@@ -124,7 +121,7 @@ export class RenameVariableCommand implements Command {
 
 const INVALID_NAME = 'Variable names must start with a letter and contain only letters, digits or _';
 
-/** Identifier-like, and not one of the common property keys (a variable "enabled" would shadow the switch). */
+/** Identifier-like, and not a common property key – a variable "enabled" would shadow the switch. */
 export function isValidVariableName(name: string): boolean {
   return /^[A-Za-z_][A-Za-z0-9_]*$/.test(name) && !isCommonProp(name);
 }