Split the object inspector, and sweep out the section banners

objectSection.ts had grown to 559 lines around three separable parts: the
queries, the vector rows and the parent row. Four object commands repeated the
same capture/restore preamble – applyCommands stays out, its five carry extra
undo state whose restore order matters.

58 dashed banner comments are gone. The nine labels in nodes/index.ts stay:
they are the only structure a flat 90-entry array has.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/runtime/World.ts

@@ -82,8 +82,6 @@ export class World {
     return this.elapsed;
   }
 
-  // --- model sync ------------------------------------------------------------------------------
-
   /**
    * Makes the entities match the scene: one entity per placed object (created on demand,
    * dropped when the object is gone), positions, names and resolved properties taken from
@@ -215,8 +213,6 @@ export class World {
     return { structure: spawned || scene.objects.length !== before, values };
   }
 
-  // --- simulation ------------------------------------------------------------------------------
-
   /** Registers a system; it starts immediately and is ticked in registration order. */
   addSystem(system: System): this {
     this.systems.push(system);
@@ -260,8 +256,6 @@ export class World {
     this.entities.length = 0;
   }
 
-  // --- queries ---------------------------------------------------------------------------------
-
   /**
    * Whether a world point lies on an entity: on the colliders of its subtree when it has
    * any, otherwise on the box of a sprite or text in it. Disabled parts never answer, so a

src/runtime/systems/Input.ts

@@ -76,7 +76,6 @@ export class Input {
     return this.released;
   }
 
-  /** Keys currently held. */
   get heldKeys(): ReadonlySet<string> {
     return this.down;
   }