Function loadBakedEnvironment

Read the baked map, or null when the store has none / it is stale / it is malformed. rootContentHash is the root content_hash from the freshly fetched root document (the same value the cache validation reads). storeKey (the normalized dataset URL) scopes the session's negative cache for probed stores; omit it to always probe. index says which root index is current: true when the store's consolidated index came from the network this load (not a cache tier), so its silence about environment is proof of absence; a EnvironmentRootListing (which can also answer from the load-time root-document fetch on a warm load); or the default false, which probes. sourceRootLoc, when given, is where the group's attrs are read whenever the opened store's own index is not network-fresh (see attrsLocation).