- quark: Collection.first(name) is now a stable Readable<A | undefined>;
Keyed.ReadOnly names the read surface; useSlot takes plain constant keys;
Layout.collectionOf<Target>() replaces the content plan double cast
- BackgroundToolHint reads a backgroundRunning first index instead of
hand-tracking structure plus tool slots
- toolDisplay moves to util/tool-display (content.ts needs it for the index)
