a re-created cache signs with a new key; the fact was only created once, so
every hive then rejected the swarm's closures. the cache's grant gains update
on that one leaf, and a store that refuses it leaves the key as it was.
Closes#6181
Every docs directory moves under 1-getting-started, 2-handbook,
4-implementation or 5-project; the options reference (section 3) comes from
the website and has no directory here. trust-boundary stays whole under the
handbook for now. web-ui, swarm and tools split between handbook and
implementation, and the command-line references move to
2-handbook/reference. Links, path references in code and nix, and the docs
index follow the moves; no page content changes.
the in-swarm cache stores its address, name and public key beside its tokens, create-only. swarm-controller copies the four cache facts to swarm/hives/<hive>/attic/* every five minutes, with read on the sources and write on the copies. part 1 of 3: nothing reads the copies until the hive reader and probe land.
