Assorted internal reshuffles

A batch of refactors with no visible effect: a value cache moved from one lookup helper to another and gained a size cap, a lazy module stopped eagerly initializing about thirty submodules, the experiment store keeps its reinitializing promise across a reset, skill-tool membership now reads two stores and filters through one call, activity refresh and debounce delays became named constants, and status-line and memory-list components dropped three unused props.