Hot swap everything

• everything, simple as /kjs reload startup-scripts
• how: JS contents live inside mutable boxes / entries registered in vanilla registries; on reload, new instances swap the inner reference in-place, so every existing reference (even saved iotas) picks up new behaviors instantly
• covers: ActionRegistryJS (entry action & prototype replaced in-place), SpecialHandlerJS, IotaJS
• not for those haven't created on startup, but it's possible to match later-created pattern actions using a special handler :3
• as for CastingEnvironmentComponentJS and MishapJS, they're born temporary, just always use the newest ones and everything is fine :3